Dungeon Terrain

Dungeons are deep, dark pits filled with subterranean horrors and lost, ancient treasures. Dungeons are labyrinths where evil villains and carnivorous beasts hide from the light, waiting for a time to strike into the sunlit lands of good. Dungeons contain pits of seething acid and, magic traps that blast intruders with fire, as well as dragons guarding their hoards and magic artifacts waiting to be discovered.

In short, dungeons mean adventure.

The Dungeon As Adventure Setting

The term "dungeon" is a loose one. A dungeon is usually underground, but an aboveground site can be a dungeon as well. Some DMs apply the term to virtually any adventure site. For this discussion, a dungeon is an enclosed, defined space of encounter areas connected in some fashion.

The most common form of dungeon is the underground complex built by intelligent creatures for some purpose. Physically, such a place has rooms joined by corridors, stairs connecting it with the surface, and doors and traps to keep out intruders. The archetypal dungeon is abandoned, with creatures other than the builders now occupying areas within it. Adventurers explore such places with the hope of finding treasure either left behind by the original inhabitants or in the hoards of such squatters.

Types of Dungeons

There are four basic dungeon types, defined by their current status. Many dungeons are variations on these basic types or combinations of more than one of them. Sometimes old dungeons are used again and again by different inhabitants for different purposes.

Ruined Structure: Once occupied, this place is now abandoned (completely or in part) by its original creator or creators, and other creatures have wandered in. Many subterranean creatures look for abandoned underground constructions in which to make their lairs. Any traps that might exist have probably been set off, but wandering beasts might very well be common.

Areas within the ruined structure usually contain clues as to their original intended use. What is now the lair of a family of rust monsters might once have been an old barracks, the rotting remains of the beds and other furnishings now arranged to make nests for the creatures. An ancient throne room, adorned with the tatters of once-beautiful tapestries, might be empty and quiet - the ancient curse that struck down the queen still hanging in the air before the verdigris-encrusted bronze throne.

The ruined structure dungeon is a place that cries out to be explored. Adventurers might hear tales of treasure still lingering in the abandoned labyrinth, leading them to brave the dangers to uncover it. This is the simplest and most straightforward of the dungeon types, and it usually balances danger (the inhabitants) with reward (the treasure). The creatures dwelling in a ruined structure aren't necessarily organized, so adventurers can usually come and go as they please, making it easy to start and stop adventures.

Occupied Structure: This dungeon is still in use. Creatures (usually intelligent) live there, although they may not be the dungeon's creators. An occupied structure might be a home, a fortress, a temple, an active mine, a prison, or a headquarters. This type of dungeon is less likely to have traps or wandering beasts, and more likely to have organized guards - both on watch and on patrol. Traps or wandering beasts that might be encountered are usually under the control of the occupants. Occupied structures have furnishings to suit the inhabitants, as well as decorations, supplies, and the ability for occupants to move around (doors they can open, hallways large enough for them to pass through, etc.). The inhabitants might have a communication system, and they almost certainly control an access to the outside.

Some dungeons are partially occupied and partially empty or in ruins. In such cases, the occupants are typically not the original builders but instead a group of intelligent creatures that have set up their base, lair, or fortification within an abandoned dungeon.

Use the occupied structure dungeon for the lair of a goblin tribe, a secret underground fortress, or an occupied castle. This is one of the most challenging types of dungeons for adventurers to enter and explore if the occupants are hostile. The challenge comes from the organized nature of the inhabitants. Its always harder to fight a foe on his own terms in an area he knows well and is prepared to defend.

Safe Storage: When people want to protect something, they might bury it underground. Whether the item they want to protect is a fabulous treasure, a forbidden artifact, or the dead body of an important figure, these valuable objects are placed within the dungeon and surrounded by barriers, traps, and guardians.

The safe storage type of dungeon is the most likely to have traps but the least likely to have wandering beasts. The crypt of an ancient lich may be filled with all manner of magic traps and guardians, but it's unlikely that any subterranean monster has moved in and made a part of the dungeon its lair - .the traps and guardians will have held them at bay This type of dungeon normally is built for function rather than appearance, but sometimes it has ornamentation in the form of statuary or painted walls. This is particularly true of the tombs of important people.

Sometimes, however, a vault or a crypt is constructed in such a way as to house living guardians. The problem with this strategy is that something must be done to keep the creatures alive between intrusion attempts. Magic is usually the best solution to provide food and water for these creatures.

Even if there's no way anything living can survive in a safe storage dungeon, certain monsters can still serve as guardians. Builders of vaults or tombs often place undead and constructs, with no need for sustenance or rest, to guard their dungeons. Magic traps can summon monsters into the dungeon to attack intruders without ever having to worry about sustaining the guardians, who disappear after they're needed.

Natural Cavern Complex: Caves underground provide homes to all sorts of subterranean monsters. Created naturally and connected by a labyrinthine tunnel system, these caverns lack any sort of pattern, order, or decoration. With no intelligent force behind its construction, this type of dungeon is the least likely to have traps or even doors.

Fungi of all sorts thrive in caves, sometimes growing up like a huge forest of mushrooms and puffballs. Subterranean predators prowl these forests, looking for those feeding upon the fungi itself Sometimes, fungus gives off an eerie phosphorescence, providing natural cavern complexes with their own limited light source. In other areas, continual flame or other magical effects can provide enough light for green plants to grow.

Often, natural cavern complexes connect with other sorts of dungeons, having been discovered when the artificial dungeon was delved. They can connect two unrelated dungeons, sometimes creating a strange mixed environment. Natural cavern complexes joined with other dungeons often provide a route by which, subterranean creatures find their way into created dungeons and, populate them. Rumors tell of the Underdark, a subterranean world that is one big natural cavern complex dungeon running under the surface of entire continents.

Natural cavern complexes can be quite beautiful, with stalactites, stalagmites, flowstone, columns, and other limestone formations. However, from an adventuring point of view they have a serious shortcoming: less treasure. Since the dungeon was not created for a specific purpose, there's little chance of happening upon a secret room filled with gold left behind by the previous occupants.

Dungeon Features

Practically all dungeons have walls, floors, doors, and other types of basic features. Many are quite elaborate. Dungeon adventurers learn the common features quickly. Use this fact to your advantage. Common features create consistency (which helps suspend disbelief) and allow you to create interesting surprises by changing the features - sometimes only slightly.


Masonry walls - stones piled on top of each other (usually, but not always, held in place with mortar) - divide dungeons into corridors and chambers. Dungeon walls can also be hewn from solid rock, leaving them with a rough, chiseled look. Or, dungeon walls can be the smooth, unblemished stone of a naturally occurring cave. Dungeon walls are difficult to break down or through, but they're generally easy to climb.

Masonry Walls: These are usually at least 1 foot thick. Often these ancient walls sport cracks and crevices, and sometimes dangerous slimes or small monsters live in these areas and wait for prey. Masonry walls stop all but the loudest noises.

Superior Masonry Walls: Sometimes masonry walls are better built (smoother, with tighter-fitting stones and less cracking), and occasionally these superior walls are covered with plaster or stucco. Covered walls often bear paintings, carved reliefs, or other decoration. Such walls are no more difficult to destroy than regular masonry walls but are more difficult to climb.

Hewn Stone Walls: Such walls usually result when a chamber or passage is tunneled our from solid rock. The rough surface of a hewn wall frequently provides small ledges where fungus grows and small creatures live (often vermin, bats, or coiled subterranean snakes). When there is an "other side" (that is, this wall separates two chambers in the dungeon), these walls are usually at least 3 feet thick; anything thinner risks collapsing from the weight of all that stone overhead.

Unworked Stone Walls: These surfaces are uneven and rarely flat. They are smooth to the touch hut filled with tiny holes, hidden alcoves, and ledges at various heights. They're also usually wet or at least damp, since it's water that most frequently creates natural caves. When there is an "other side", these walls are usually at least 5 feet thick.

Special Walls: Sometimes you can place special walls in a dungeon. Expect players to react with curiosity and suspicion when their characters encounter these exceptional walls.

Reinforced Walls: These are masonry walls with iron bars on one or both sides of the wall, or placed within the wall itself to strengthen it. The hardness of the reinforced wall remains the same, but the hit points are doubled and the DC to break through is increased by 10.

Magically Treated Walls: These walls are stronger than average, with a greater hardness, more hit points, and a higher break DC. Magic can usually double the hardness and hit points and can add up to +20 to the break DC. A magically treated wall also gains a saving throw against spells that could affect it, with the save bonus equaling 2 + half the caster level of the magic reinforcing the wall. Creating a magic wall is just like creating a wondrous item.

Iron Walls: These walls are placed within dungeons around important places such as vaults.

Paper Walls: Paper walls are the opposite of iron walls, placed as screens to prevent sight but nothing more.

Wooden Walls: Wooden walls often exist as recent additions to older dungeons, used to create animal pens, storage bins, or just to make a number of smaller rooms our of a larger one.

Walls with Arrow Slits: Walls with arrow slits can be made of any durable material but are most commonly masonry, hewn stone, or wood. They allow defenders to fire arrows or crossbow bolts at intruders from behind the safety of the wall, Such archers have nine-tenths cover, gaining them a +10 bonus to Armor Class.

Wall TypeTypical ThicknessBreak DCHardnessHit Points*Climb DC
Masonry1 ft.35890 hp15
Superior masonry1 ft.35890 hp20
Reinforced masonry1 ft.458180 hp15
Hewn stone3 ft.508540 hp22
Unworked stone5 ft.658900 hp20
Iron3 in.301090 hp25
PaperPaper-thin1-1 hp30
Wood6 in.20560 hp21
Magically treated**-+20x2x2***
*Per 10-ft-by-10-ft. section.
**These modifiers can be applied to any of the other categories and types.
***Or 50, whichever is greater.


As with walls, dungeon floors come in many types.

Flagstone Floors: Like masonry walls, flagstone floors are made of fitted stones. They are usually cracked and only somewhat level. Slime and mold grows in these cracks. Sometimes water runs in rivulets between the stones or sits in stagnant puddles. Over time, these floors can become so uneven that a Dexterity check (DC 13) is required if someone attempts to run across the surface. Those failing the check fall, halting their movement and requiring a move-equivalent action to stand again. Floors this treacherous should be the exception, not the rule.

Hewn Stone Floors: Rough and uneven, hewn loots are usually covered with loose stones, gravel, dirt, other debris. The floors of older dungeons may be worn fairly smooth by the passage of many feet over the years, but newer hewn floors can be as dangerous to run across as an older flagstone construction (see above).

Smooth Stone Floors: Finished and sometimes even polished, smooth floors are found only in dungeons with capable and careful builders. (They are a hallmark of dwarf-delved dungeons.) Sometimes mosaics are set in the floor, some depicting interesting images and others just smooth marble. Smooth dungeon floors may have wooden planks laid over the top of them greatly increasing the comfort of the dungeon as a dwelling, but such floorings rot in just a few years, so they are rare.

Natural Stone Floors: The floors of natural caves areas uneven as the walls. Caves rarely have large flat surfaces. Rather, their floors have many levels. Some adjacent floor surfaces might vary in elevation by only a foot, so that moving from one to the other is no more difficult than negotiating a stair, but in other places the floor might suddenly drop off or rise up several feet or more, requiring Climb checks to get from one surface to the other. Unless a path has been worn and well marked in the floor of a natural cave, running and charging in this environment are usually impossible.

Special Floors: A number of strange floorings and floor features exist to make a dungeon more interesting.

Grates: Grates cover pits or areas lower than the main floor. They are usually made from iron, but large grates can also be made from iron-bound timbers. Many grates have hinges to allow access to what lies below (such grates can be locked like any door), while others are permanent and unmoving. A typical 1-inch-thick iron grate has 25 hit points, a hardness of 10, and a DC of 27 to break through or tear away.

Ledges: Ledges allow creatures to walk above some lower area. They often circle around pits, run along underground streams, form balconies around large rooms, or provide a place for archers to stand while firing upon enemies below. Narrow ledges (less than 1 foot wide) require those moving along them to make Balance checks. Ledges covered in water, slime, or some other slippery substance are dangerous. Slipperiness adds +5 to the DC determined above. A Balance check (DC 17) is needed to traverse even wide ledges (more than 1 foot wide, but less than 2 1/2 feet) at normal speed (DC 15 if the character is willing to walk at half speed). Failure results in the moving character falling off the ledge.

Bridges: Bridges are like ledges, but they connect to higher areas separated by a lower area. Bridges stretch across chasms, over rivers, or above pits. A simple bridge might be a single wooden plank, while an elaborate one could be made of mortared stone with iron supports and side rails. Narrow bridges are treated just like ledges.

Transparent Floors: Transparent floors, made of reinforced glass or magic materials (even a wall of force), allow a dangerous setting to be viewed safely from above. Transparent floors are sometimes placed over lava pools, arenas, monster dens, and torture chambers. They can be used by defenders to watch key areas for intruders.

Trick Floors: Trick floors are designed to become suddenly dangerous. With the application of just the right amount of weight, or the pull of a lever somewhere nearby, spikes protrude from the floor, gouts of steam or flame shoot up from hidden holes, or the entire floor tilts. These strange floors are usually found in an arena area and are designed to make combats more exciting and deadly

Sliding Floors: Sliding floors are really more of a type of trapdoor, since they normally reveal something underneath. Sliding floors generally move so slowly that anyone standing on one can avoid falling into the gap it creates, assuming there's somewhere else to go. However, some can be constructed so that a Balance check (DC 15) is required to keep from falling into whatever lies below the sliding floor - a spiked pit, a vat of burning oil, or a pool filled with sharks (or perhaps just mutant sea bass).


Doors in dungeons are much more than mere entrances and exits, Often they can be encounters all by themselves. After all, anything that can trigger a nasty trap, offer you a clue, zap you with a spell, or simply block your way deserves serious attention from the dungeon explorer. The doorways they are set in may be plain arches and lintels, or maybe festooned with carvings - often gargoyles or leering faces but sometimes carved words that might reveal a clue to what lies beyond. Dungeon doors come in three basic types: wooden, stone, and iron.

  Break DC
Door TypeTypical ThicknessHardnessHit PointsStuckLocked
Simple wooden1 in.510 hp1315
Good wooden1 1/2 in.515 hp1618
Strong wooden2 in.520 hp2325
Stone4 in.860 hp2828
Iron2 in.1060 hp2828
Portcullis, wooden 3 in530 hp25*25*
Portcullis, iron2 in.1060 hp25*25*
Lock-1530 hp 
Hinge-1530 hp 
*DC to lift. Use appropriate door figure for breaking

Wooden Doors: Constructed of thick planks nailed together, sometimes bound with iron for strength (and to reduce swelling from dungeon dampness), wooden doors are the most common type. Wooden doors come in varying strengths: simple, good, and strong doors. Simple doors (break DC 13) are not meant to keep our motivated attackers. Good doors (break DC 18), while sturdy and long-lasting, are still not meant to take much punishment. Strong doors (break DC 23) are bound in iron and are a fairly good barrier to those attempting to get past them.

Iron hinges fasten the door to its frame, and typically a circular pull-ring in the center is there to help open it. Since most doors only open in one direction, the pull-ring is located only on the side toward which the door opens (the side with the hinges). Sometimes, instead of a pull-ring, a door has an iron pull-bar on one or both sides of the door to serve as a handle. In inhabited dungeons, these doors are usually well maintained (not stuck) and unlocked, although important areas are locked up if possible,

Stone: Carved from solid blocks of stone, these heavy, unwieldy doors are often built so that they pivot when they are opened, although dwarves and other skilled craftsfolk are able to fashion hinges strong enough to hold up a stone door. Secret doors concealed within a stone wall are usually stone doors. Otherwise, such doors stand as tough barriers protecting something important beyond. Thus, they are often locked or barred.

Iron: Rusted but sturdy, iron doors in a dungeon are hinged like wooden doors. These doors are the toughest form of nonmagical door. They are usually locked or barred.

Random doors

Door Locks, Bars, Seals, and Traps

Dungeon doors may be locked, trapped, enchanted, reinforced, barred, magically sealed, or sometimes just stuck. All but the weakest characters can eventually knock down a door with a heavy tool such as a sledgehammer, and a number of spells and magic items give characters an easy way around a locked door. Attempts to literally chop a door down with an axe use the hardness and hit points given in Doors. Often the easiest way to overcome a recalcitrant door is not by demolishing it but by breaking its lock, bar, or hinges. When assigning DCs to attempts to knock a door down, use the following as guidelines:

Locks: Dungeon doors are often locked, and thus the Open Lock skill comes in very handy Locks are usually built into the door, either on the edge opposite the hinges or right in the middle of the door. Built-in locks either control an iron bar that juts out of the door and into the wall of its frame, or else a sliding iron bar or heavy wooden bar that rests behind the entire door. By contrast, padlocks are not built-in but usually run through two rings, one on the door and the other on the wall. More complex locks, such as combination locks and puzzle locks, are usually built into the door itself. Since such keyless locks are expensive, they are typically only found in sturdy doors (iron-bound wooden, stone, or iron doors).

The DC to pick a lock with an Open Lock check often falls into the range of DC 20 to DC 30, although locks with lower or higher DCs can exist. A door can have more than one lock, each of which must be unlocked separately. Locks often are trapped, usually with poison needles that extend our to prick a rogue's finger.

Breaking a lock is sometimes quicker than breaking the whole door. If a PC wants to whack at a lock with a weapon, treat the typical lock as having a hardness of 15 and 30 hit points. A lock can only be broken if it can be attacked separately from the door, which means that a built-in lock is immune to this sort of treatment. Keep in mind that in an occupied dungeon, every locked door has a key somewhere. If the adventurers are unable to pick a lock or break down the door, finding whoever has the key and getting it away from its possessor can be an interesting part of the adventure.

A special door (see below for examples) might have a lock with no key, instead requiring that the right combination of nearby levers must be manipulated or the right symbols must be pressed on a keypad in the correct sequence to open the door. You're perfectly justified in ruling that some puzzle doors must be solved by the players rather than being bypassed by an Open Lock check - for example, if a door only unlocks when the riddle carved on it is correctly answered, then it's up to the players to solve the riddle.

Stuck Doors: Dungeons are often damp, and sometimes doors get stuck, particularly wooden doors. Assume that about 10% of wooden doors and 5% of non-wooden doors are stuck. These numbers can be doubled (to 20% and 10%, respectively) for long-abandoned or neglected dungeons.

Hinges: Most doors have hinges. Obviously, sliding doors do not. (They usually have tracks or grooves instead, allowing them to slide easily to one side.)

Standard Hinges: These hinges are metal, joining one edge of the door to the doorframe or wall. Remember that the door swings open toward the side with the hinges. (So if the hinges are on the PCs' side, the door opens toward them; otherwise it opens away from them.) Adventurers can take the hinges apart one at a time with successful Disable Device checks (assuming the hinges are on their side of the door, of course). Such a task has a DC of 20, since most hinges are rusted and stuck. Breaking a hinge is difficult. Most have a hardness of 15 and 30 hit points. The break DC for a hinge is the same as for breaking down the door (see Door Types).

Nested Hinges: These hinges are much more complex, and are found only in areas of excellent construction, such as an underground dwarven citadel. These hinges are built into the wall and allow the door to swing open in either direction. PCs can't get at the hinges to fool with them unless they break through the door-frame or wall. Nested hinges are typically found on stone doors but sometimes occur on wooden or iron doors.

Pivots: Pivots aren't really hinges at all, but simple knobs jutting from the top and bottom of the door that fit into holes in the doorframe, allowing the door to spin. The advantages of pivots are that they can't be dismantled like hinges and they're simple to make. The disadvantage is that since the door pivots on its center of gravity (typically in the middle), nothing larger than half the door's width can fit through. Doors with pivots are usually stone and are often quite wide to overcome this disadvantage. Another solution is to place the pivot toward one side and have the door be thicker at that end and thinner toward the other end so that it opens more like a normal door. Secret doors in walls often pivot, since the lack of hinges makes it easier to hide the door's presence. Pivots also allow objects such as bookcases to be used as secret doors.

Door Traps: More than just about any other facet of a dungeon, doors are protected by traps, The reason is pretty obvious - an open door means an intruder. A mechanical trap can be connected to a door by wires or springs so that it activates when the door is opened - firing an arrow, releasing a cloud of gas, opening a trap door, letting loose a monster, dropping a heavy block on intruders, or whatever. Magic traps such as glyphs of warding typically are cast directly on the door, blasting intruders with flame or some other magical attack.

Example: A magic door is trapped with a sequence of spells (programmed image and teleport or dimension door). When the door is opened, an illusion of a dragon's head reaches forth out of the darkness beyond and appears to swallow the opener whole, receding back into the darkness and no doubt leaving the rest of the adventurers with mouths agape. In reality, the opener was teleported into a nearby prison cell filled with the bones of previous explorers who fell victim to the same trap. Only if the rest of the PCs are brave enough to press onward can they find their comrade and free him. (Of course, for all they know, he's been killed and eaten....)

Special Doors: An interesting facet of a dungeon might be a sealed door too strong to break down. Such a door might be opened only by operating secret switches, or hidden (and distant) levers. Crafty builders make using the switches or levers more difficult by requiring that they be used in a special way. For example, a particular door might only open if a series of four levers is moved into a specific configuration - two pushed up, and two pushed down. If a lever in the series is put in the wrong position, it springs a trap. Now imagine how much more difficult it would be if there were a dozen or more levers, with multiple settings, spread out through the entire dungeon. Finding the method to open a special door (perhaps leading into the vault, the vampire's lair, or the dragon's secret temple) can be an adventure in itself.

Sometimes a door is special because of its construction. A lead-lined door, for example, provides a barrier against many detection spells. A heavy iron door might be built in a circular design, rolling to one side on a track once it is opened. A mechanical door linked with levers or winches might not open unless the proper mechanism is activated. Such doors often sink into the floor, rise up into the ceiling, lower like a drawbridge, or slide into the wall rather than merely swinging open like a normal door.

Magic Doors: Enchanted by the original builders, a door might speak to explorers, warning them away. It might be protected from harm, increasing its hardness or giving it more hit points as well as an improved saving throw bonus against disintegrate and other similar spells. A magic door might not lead into the space revealed beyond, but instead it might be a portal to a faraway place or even another plane of existence. A door magically shaped from a wall of force would resist spells as well as any attempt to break it down (short of a disintegrate spell). Other magic doors might require passwords or special keys (ranging from the tail feather of an evil eagle, to a note played upon a lute, to a certain frame of mind) to open them. Effectively, the range and variety of magic doors is limited only by your imagination.

Portcullises: These special doors consist of iron or ironbound, thick, wooden shafts that descend from a recess in the ceiling above an archway Sometimes they have crossbars that create a grid, sometimes not. Typically raised by means of a winch or a capstan, a portcullis can be dropped quickly, and the shafts end in spikes to discourage anyone from standing underneath (or from attempting to dive under as it drops). Once it is dropped, a portcullis locks, unless it is so large that no normal person could lift it anyway. In any event, lifting a typical portcullis requires a Strength check (DC 25).

Walls, Doors, And Detect Spells

Stone walls, iron walls, and iron doors are usually thick enough to block most detect spells, such as detect thoughts. Wooden walls, wooden doors, and stone doors are usually not thick enough to do so. However, a secret stone door built into a wall and as thick as the wall itself (at least 1 foot) does block most detect spells.


Rooms in dungeons vary in shape and size. Although many are simple in construction and appearance, particularly interesting rooms have multiple levels joined by stairs, ramps, or ladders as well as statuary, altars, pits, chasms, bridges, and more.

Keep three things in mind when designing a dungeon room:


Stretching into the darkness, a mysterious cobweb-filled passage deeper into the dungeon can be intriguing and a little frightening. All dungeons have rooms, and most have corridors. While most corridors simply connect rooms, sometimes they can be encounter areas in their own right due to traps, guard patrols, and wandering monsters out on the hunt.

When designing a dungeon, make sure that the corridors are large enough for the dungeon residents to use. (For example, a dragon needs a pretty big tunnel to get in and out of its lair.) Wealthy, powerful, or talented dungeon builders may favor wide corridors to give a grand appearance to their residence. Otherwise, passages are no larger than they need to be. (Tunneling through solid rock is expensive, back-breaking, time-consuming work.) Corridors narrower than 10 feet can make it difficult for all the members of the PC party to get involved in any fights that occur, so make them the exception rather than the rule.

Corridor Traps: Because passageways in dungeons tend to be narrow, offering few movement options, dungeon builders like to place traps in them. In a cramped passageway, there's no way for intruders to move around concealed pits, falling stones, arrow traps, tilting floors, and sliding or rolling rocks that fill the entire passage. For the same reason, magic traps such as glyphs of warding are effective in hallways as well.

Mazes: Usually, passages connect chambers in the simplest and straightest manner possible. Some dungeon builders, however, design a maze or a labyrinth within the dungeon. These are difficult to navigate (or at least to navigate quickly) and, when filled with monsters or traps, can be an effective barrier. Mazes cut off one area of the dungeon, deflecting intruders away from a protected spot. Generally, though, the far side of a maze holds an important crypt or vault - someplace that the dungeon's intended inhabitants rarely need to get to.

Miscellaneous Features

Any dungeon is made more interesting by the inclusion of some or all of these features.

Stairs: The usual way to connect different levels of a dungeon is with stairs. Straight stairways, spiral staircases, or stairwells with multiple landings between flights of stairs are all common in dungeons, as are ramps (sometimes with an incline so slight that it can be difficult to notice - DC 15 Spot check). Stairs are important accessways, and are sometimes guarded or trapped. Traps on stairs often cause intruders to slide or fall down to the bottom, where a pit, spikes, a pool of acid, or some other dangers await.

Chutes and Chimneys: Stairs aren't the only way to move up and down in the dungeon. Sometimes a vertical shaft connects levels or links the dungeon with the surface. Chutes are usually traps that dump characters into a lower area - often a place with some dangerous situation with which they must contend.

Pillars: A common sight in any dungeon, pillars and columns give support to ceilings. The larger the room, the more likely it has pillars. Pillars can be anywhere from 1 foot to 5 feet in diameter - as a rule of thumb, the deeper in the dungeon, the thicker the pillars need to be to support the overhead weight. Some pillars are large enough for characters (and some monsters) to hide behind, creating some interesting tactical possibilities. Pillars tend to be polished and often have carvings, paintings, or inscriptions upon them.

Statues: Reflections of bygone days, statues found in dungeons can be realistic depictions of persons, creatures, or scenes, or they can be less lifelike in their imagery. Statues often serve as commemorative representations of people from the past as well as idols of gods. Statues may be either painted or left bare. Some have inscriptions. Adventurers wisely distrust statues in dungeons for fear that they may animate and attack, as a stone golem can do. Statues in a dungeon could also be a sign indicating the presence of a monster with a petrifying power (medusa, cockatrice, etc.). Feel free to utilize both of these ideas, but don't forget that sometimes a statue is just a statue.

Tapestries: Elaborately embroidered patterns or scenes on cloth, tapestries hang from the walls of well-appointed dungeon rooms or corridors. They not only make chambers more comfortable as a residence but can add a ceremonial touch to shrines and throne rooms. Crafty builders rake advantage of tapestries to place alcoves, concealed doors, or secret switches behind them. Sometimes the images in a tapestry contain clues to the nature of the builders, the inhabitants, or the dungeon itself

Secret Doors: Disguised, as a bare patch of wall (or floor, or ceiling), a bookcase, a fireplace, or a fountain, a secret door leads to a secret passage or room. Someone examining the area finds a secret door, if any, on a successful Search roll (DC 20 for a typical secret door to DC 30 for a well-hidden secret door). Remember that elves have a chance to detect a secret door just by casually looking at the area. Many secret doors require a special method of opening, such as a hidden button or pressure plate. Secret doors can open like normal doors, or they may pivot, slide, sink, rise, or even lower like a drawbridge to permit access. Builders might put a secret door down low near the floor or high up in a wall, making it difficult to find or reach. Wizards have a spell, phase door, that allows them to create a magic secret door that only they can use.

Daises and Pedestals: Anything important on display in a dungeon, from a fabulous treasure to a coffin, tends to rest atop a dais or a pedestal. Raising the object off the floor focuses attention on it (and, in practical terms, keeps it safe from any water that might seep onto the floor). A dais or a pedestal is often trapped to protect whatever sits atop it. It can conceal a secret trap door beneath itself or provide a way to reach a door in the ceiling above itself.

Vaults: Well protected, often by a locked iron door, a vault is a special room that contains treasure. There's usually only one entrance - an appropriate place for a trap.

Crypts: Although sometimes constructed like a vault, a crypt can also be a series of individual rooms, each with its own sarcophagus, or a long hall with recesses on either side - shelves to hold coffins or bodies. Wise adventurers expect to encounter undead in a crypt, but are often willing to risk it to look for the treasure that's often buried with the dead. Crypts of most cultures are well appointed and highly decorated, since the fact that the crypt was created at all shows great reverence for the dead entombed within.

People worried about undead rising from the grave take the precaution of locking and trapping a crypt from the outside - making the crypt easy to get into but difficult to leave. Those worried about tomb robbers make their crypts difficult to get into. Some builders do both, just to be on the safe side.

Pools: Pools of water collect naturally in low spots in dungeons (a dry dungeon is rare). Pools can also be wells or natural underground springs. Or they can be intentionally created basins, cisterns, and fountains. In any event, water is fairly common in dungeons. Deep pools harbor sightless fish and sometimes worse - aquatic monsters. Pools provide water for dungeon denizens, and thus are as important an area for a predator to control as a watering hole aboveground in the wild.

Through accident or design, pools can become polluted or even enchanted. While this usually just makes the water foul or tainted, rarely a pool or a fountain gains the ability to bestow enchantment on those who drink from it - healing, ability score modification, transmutation magic, or even something as amazing as a wish spell. However, enchanted pools are just as likely to curse the drinker, causing a loss of health, an unwanted polymorph, or some even greater affliction. Typically water from a magic pool loses its potency if removed from the pool for more than an hour or so.

Some pools have fountains. Occasionally these are merely decorative, but they often serve as the focus of a trap or the enchanted functioning of a magic pool.

Elevators: In place of or in addition to stairs, elevators (essentially over-sized dumbwaiters) can take inhabitants from one dungeon level to the next. Such elevators may be mechanical (using gears, pulleys, and winches) or magical (Tenser's floating disk, etc.). A mechanical elevator might be as small as a platform that holds one character at a time, or as large as an entire room that raises and lowers. A clever builder might design an elevator room that moves up or down without the occupants' knowledge to catch them in a trap, or one that appears to have moved when it actually remained still.

Shifting Stones or Walls: These features can cut off access to a passage or room, trapping adventurers in a dead end or preventing escape out of the dungeon. Shifting walls can force explorers to go down a dangerous path or prevent them from entering a special area. Not all shifting walls need be traps. For example, stones controlled by pressure plates, counterweights, or p a secret lever can shift out of a wall to become a staircase leading to a hidden upper room or secret ledge.

Teleporters: Sometimes useful, sometimes devious, places in dungeons rigged with a teleportation effect (such as a teleportation circle) transport characters to some other location in the dungeon or someplace far away. They can be traps, teleporting the unwary into dangerous situations, or they can be an easy mode of transport for those who built or live in the dungeon, good for bypassing barriers and traps or simply to get around more quickly. Devious dungeon designers might place a teleporter in a room that transports characters to another seemingly identical room so that they don't even know they've been teleported.

Altars: Temples - particularly to dark gods - often exist underground. Usually taking the form of a simple stone block, the altar is the main fixture and central focus of such a temple. Sometimes all the trappings of the temple are long gone, lost to theft, age, and decay, but the altar itself survives. Surely there's some divine power or connection there still....

Major Furnishings and Features

Dungeon Dressing - Major Features and Furnishings is a list of large or predominant features commonly found in dungeons. Or use the Random Dungeon Dressing generator when creating a random dungeon or to round out one you are creating.

Minor Furnishings and Features

Adventures can come across small bits and contents of dungeon rooms while exploring. Use Dungeon Dressing - Minor Features and Furnishings as an idea generator when creating a random dungeon or to round out one you are creating. Or use the Random Dungeon Dressing generator

Obstacles, Hazards, And Traps

In a dungeon, adventurers can fall to their deaths, be burned alive, or find themselves peppered with poisoned darts - all without ever having encountered a single monster. Dungeons tend to be filled with barriers or life-threatening traps of one kind or another. The following sections lay down some basic rules for handling common obstacles and traps. Remember that you are always free to modify the DC or other details to reflect specific conditions in your dungeon.


One of the most common hazards to adventurers is a fall from some great height.

Falling Damage: The basic rule is simple: 1d6 points of damage per 10 feet fallen, to a maximum of 20d6.

If a character deliberately jumps instead of merely slipping or falling, the damage is the same but the first 1d6 is subdual damage. A successful jump check (DC 15) allows the character to avoid any damage from the first 10 feet fallen and converts any damage from the second 10 feet to subdual damage. Thus, a character who slips from a ledge 30 feet up takes 3d6 damage. If the same character deliberately jumped, he takes 1d6 points of subdual damage and 2d6 points of normal damage. And if the character leaps down with a successful Jump check, he takes only 1d6 subdual damage and 1d6 normal damage from the plunge.

Falls onto yielding surfaces (soft ground, mud) also convert the first 1d6 to subdual damage. This reduction is cumulative with reduced damage due to deliberate jumps and rho Jump skill.

Falling into Water: Falls into water are handled somewhat differently. So long as the water is at least 10 feet deep, the first 20 feet of falling do no damage. The next 20 feet do subdual damage (1d3 per 10-foot increment). Beyond that, falling damage is normal damage (1d6 per additional 10-foot increment).

Characters who deliberately dive into water take no damage on a successful Swim or Tumble check (DC 15), so long as the water is at least 10 feet deep for every 30 feet fallen. However, the DC of the check increases by 5 for every 50 feet of the dive.

Variant: Generous DMs who feel that falling is too lethal can make the first 1d6 of falling damage always subdual damage, no matter what the circumstances.

Pits and Chasms

Pits in dungeons come in three basic varieties: uncovered, covered, and chasms. Like a cliff or a wall, a pit or a chasm forces characters to either detour around or go through the time and trouble of figuring our a way across. Pits and chasms can be defeated by judicious application of the Climb skill, the Jump skill, or various magical means.

Uncovered pits serve mainly to discourage intruders from going a certain way, although they cause much grief to characters who stumble into them in the dark, and they can greatly complicate a melee taking place nearby.

Covered pits are much more dangerous. They can be detected with a Search check (DC 20), hut only if the character is taking the time to carefully examine the area before walking across it. A character who fails to detect a covered pit is still entitled to a Reflex save (DC 20) to avoid falling into it. However, if she was running or moving recklessly at the time, she gets no saving throw and falls automatically.

Trap coverings can be as simple as piled refuse (straw, leaves, sticks, garbage), a large rug, or an actual trapdoor concealed to appear as a normal part of the floor. Trapdoors usually swing open when enough weight (usually about 50 to 80 pounds) is placed upon them. Devious trap builders sometimes design trapdoors so that they swing back shut after they open, for the next victim. A variant of this is to have the trapdoor lock once it's back in place, leaving the stranded character well and truly trapped. Opening such a trapdoor is just as difficult as opening a regular door (assuming the character can reach it at all), and a Strength check (DC 13) is needed to keep a spring-loaded door open.

Pit traps often have something nastier than just a hard floor at the bottom. Trap designers may put spikes, monsters, or a pool of acid, lava, or even water at the bottom (since even a victim proficient in swimming eventually will tire and drown if trapped long enough).

Spikes at the bottom of a pit may impale unlucky characters. Such spikes deal damage as daggers with a +10 attack bonus and a +1 damage bonus for every 10 feet of the fall (to a maximum damage bonus of +5). If there are multiple spikes, the falling victim is attacked by 1d4 of them. Naturally, all this damage is in addition to any damage from the fall itself.

Monsters sometimes live in pits - oozes and jellies find that plenty of food comes to them if the trapped area is well traveled. Any monster that can fit into the pit might have been placed there by the dungeon's designer, or might simply have fallen in and not been able to climb back out. In the latter case, either it hasn't been there long, or something has been feeding it. If the pit has water, the builder may have stocked it with piranhas or other carnivorous fish. When all is said and done, though, monsters that need no upkeep - such as undead and constructs-make the best choices for creatures to inhabit a pit.

A secondary trap, mechanical or magical, at the bottom of a pit can be particularly deadly. Activated by the falling victim, the secondary trap attacks the already injured character when she's least ready for it. Arrow traps, blasts of flame, sprays of acid, magic symbols or glyphs of warding, or even magic monster summoning devices can all be found at the bottoms of pits.

Cave-Ins and Collapses

Cave-ins and collapsing tunnels are extremely dangerous. Not only do dungeon explorers face the danger of being crushed by tons of falling rock, even if they survive they may be pinned beneath a pile of rubble or cut off from the only known exit. A cave-in buries anyone in the middle of the collapsing area, and then sliding debris damages anyone in the periphery of the collapse. A typical corridor subject to a cave-in might have a bury zone 30 feet long and a slide zone of 10 feet at either end of the bury zone.

A weakened ceiling can be spotted by a successful Knowledge (architecture and engineering) or Craft (stonemasonry) check (DC 20). Remember that Craft checks can be made untrained as Wisdom checks. A dwarf can make such a check if he simply passes within 10 feet of a weakened ceiling.

A weakened ceiling may collapse under the impact of a major impact or concussion. A character can cause a cave-in by dealing 20 points of damage to the weakened ceiling or by breaking it with a successful Strength check (DC 24). A weakened ceiling also collapses if this damage is done to the columns or pillars supporting it rather than directly to the ceiling itself.

Characters in the bury zone of a cave-in sustain 8d6 points of damage, or half that amount if they make a successful Reflex saving throw (DC 15). They are subsequently pinned. Characters in the slide zone sustain 3d6 points of damage, or no damage at all if they make a successful Reflex saving throw (DC 15). Characters in the slide zone who fail their saves are pinned.

Pinned characters take 1d6 points of subdual damage per minute while pinned. If such a character falls unconscious, he must make a Constitution check (DC 15). If the character fails, he takes 1d6 points of normal damage each minute thereafter until freed or dead.

Characters who aren't buried can dig out their friends. In 1 minute, using only her hands, a character can clear rocks and debris equal to five times her heavy load rating (see Carrying Capacity). The amount of loose stone that fills a 5-foot-by-5-foot area weighs one ton (2,000 pounds). Therefore, the average adventurer (Str 10, heavy load 100 lb.) takes 4 minutes to clear a 5-foot cube filled with stone (100 lb. x 5 = 500 lb., 500 lb. x 4 = 2,000 lb.). A half-orc with 20 Strength (heavy load 400 lb.) can accomplish the same feat in 1 minute (400 lb. x 5 = 2,000 lb.). Armed with an appropriate tool, such as a pick, crowbar, or shovel, a digger can clear loose stone twice as quickly as by hand. You may allow a pinned character to free himself with a successful Strength check (DC 25).

Mechanical Traps

Dungeons are frequently equipped with fiendish mechanical (nonmagical) traps, such as hidden crossbows that fire when the victim unwittingly steps on a trigger plate on the floor, or hallways rigged to collapse in a deadly cave-in. A trap typically is defined by its location and triggering conditions, how hard it is to spot before it goes off, how much damage it deals, and whether or not the heroes receive a saving throw to mitigate its effects. Traps that attack with arrows, sweeping blades, and other types of weaponry make normal attack rolls, with an attack bonus as determined by the Dungeon Master.

Creatures who succeed at a Search check (DC 20) detect a simple mechanical trap before it is triggered. (A simple trap is a snare, a trap triggered by a tripwire, or a large trap such as a pit.)

A rogue (and only a rogue) who succeeds at a Search check (DC 21) detects a well-hidden or complex mechanical trap before it is triggered. Complex traps are denoted by their triggering mechanisms and involve pressure plates, mechanisms linked to doors, changes in weight, disturbances in the air, vibrations, and other sorts of unusual triggers.

Building Mechanical Traps

Like any other form of crafting, the building of mechanical traps requires the proper materials, time, and the appropriate Craft skill (in this case, Craft [trapmaking]). As a rough estimate, assume that a trap costs 1,000 gp and requires one week to construct per point of Challenge Rating. Thus a typical portcullis trap (CR 2) costs 2,000 gp and requires two weeks to construct. See Chapter 7 (DMG): Rewards for rules on assigning Challenge Ratings to traps.

Simple Mechanical Traps

The following are common mechanical traps, found in dungeons the world over. Provided for each trap is its Challenge Rating (CR), its attack bonus (when applicable), the amount of damage it inflicts (in parentheses), and the DCs for saving throws or skill checks to find, avoid, and/or disable the trap.

Arrow Trap: CR 1; +1.0 ranged (1d6/x3 crit); Search (DC 20); Disable Device (DC 20). Note: 200-ft. max range, target determined randomly from those in its path.

Spear Trap: CR 2; +12 ranged (1d8/x3 crit); Search (DC 20); Disable Device (DC 20). Note: 200-ft. max range, target determined randomly from those in its path.

Pit Trap (20 Ft. Deep): CR 1; no attack roll necessary (2d6); Reflex save (DC 20) avoids; Search (DC 20); Disable Device (DC 20).

Spiked Pit Trap (20 Ft. Deep): CR 2; no attack roll necessary (2d6), +10 melee (1d4 spikes for 1d4+2 points of damage per successful hit); Reflex save (DC 20) avoids; Search (DC 20); Disable Device (DC 20).

Pit Trap (40 Ft. Deep): CR 2; no attack roll necessary (4d6); Reflex save (DC 20) avoids; Search (DC 20); Disable Device (DC 20).

Spiked Pit Trap (40 Ft. Deep): CR 3; no attack roll necessary (4d6), +10 melee (1d4 spikes for 1d4+4 points of damage per successful hit); Reflex save (DC 20) avoids; Search (DC 20); Disable Device (DC 20).

Pit Trap (60 Ft. Deep): CR 3; no attack roll necessary (6d6); Reflex save (DC 20) avoids; Search (DC 20); Disable Device (DC 20).

Spiked Pit Trap (60 Ft. Deep): CR 4; no attack roll necessary (6d6), +10 melee (1d4 spikes for 1d4+5 points of damage per successful hit); Reflex save (DC 20) avoids; Search (DC 20); Disable Device (DC 20).

Pit Trap (80 Ft. Deep): CR 4; no attack roll necessary (8d6); Reflex save (DC 20) avoids; Search (DC 20); Disable Device (DC 20).

Spiked Pit Trap (80 Ft. Deep): CR 5; no attack roll necessary (8d6), +10 melee (1d4 spikes for 1d4x5 points of damage per successful hit); Reflex save (DC 20) avoids; Search (DC 20); Disable Device (DC 20).

Pit Trap (100 Ft. Deep): CR 5; no attack roll necessary (10d6); Reflex save (DC 20) avoids; Search (DC 20); Disable Device (DC 20).

Spiked Pit Trap (100 Ft. Deep): CR 6; no attack roll necessary (10d6), +10 melee (1d4 spikes for 1d4+5 points of damage per successful hit); Reflex save (DC 20) avoids; Search (DC 20); Disable Device (DC 20).

Poison Needle Trap: CR 2; +8 ranged (1, plus greenblood oil poison); Search (DC 22); Disable Device (DC 20). Note: See greenblood oil poison.

Hail of Needles: CR 1; +20 ranged (2d4); Search (DC 22); Disable Device (DC 22).

Crushing Wall Trap: CR 10; no attack roll required (20d6); Search (DC 20); Disable Device (DC 25).

Scything Blade Trap: CR 1; -i-S melee (1d8/x3 crit); Search (DC 21); Disable Device (DC 20).

Falling Block Trap: CR 5; +15 melee (6d6); Search (DC 20); Disable Device (DC 25). Note: Can strike all characters in two adjacent specified squares (see Falling Objects).

Large Net Trap: CR 1; +5 melee (see note); Search (DC 20); Disable Device (DC 25). Note: Characters in 10-ft. square are grappled by net (Str 18) if they fail a Reflex save (DC 14).

Poison Gas Trap: CR 10; no attack roll necessary (see note below); Search (DC 21); Disable Device (DC 25). Note: Trap releases burnt othur fumes (see Poison).

Flooding Room Trap: CR 5; no attack roll necessary (see note below); Search (DC 20); Disable Device (DC 25). Note: Room floods in 4 rounds (see The Drowning Rule).

Portcullis Trap: CR 2; +10 melee (3d6/x2 crit); Search (DC 20); Disable Device (DC 20). Note: Damage applies only to those underneath the portcullis. Portcullis blocks passageway.

Random Dungeon Dressing generator - Mechanical Traps

Magic Traps

Many spells can be used to create dangerous traps. For example, high-level clerics can create glyphs of warding or symbols to prevent intruders from entering a particular area, while high-level wizards can create fire traps or permanent images to conceal dangers or confuse invaders. Unless the spell or item description states otherwise, assume the following to be true:

Creating Magic Traps

Creating a magic trap costs experience points and gold, just like creating magic items. If a trap is a one-use device, the cost for creation is 50 gp and 2 XP, both multiplied by the caster level. If a trap has multiple uses (or functions continually), the cost for creation is 500 gp and 20 XP, both multiplied by the caster level. Devising and placing a magic trap not covered by existing spell effects is just like creating a magic item (see Magic Items). Building a trap-filled dungeon filled with magical dangers is thus a costly process.

The spells listed in Spells for Magic Traps can create interesting magic traps. Use the list to pick from, get ideas, or generate traps randomly. Keep in mind that this list does not respect power level, and some effects may be clearly underpowered or overpowered for a given encounter.

Sample - Magic traps

Magic traps come in all shapes and forms. Only the power and deviousness of their creators limit them. The following are merely a few examples of the simpler magic traps. Provided for each trap is its Challenge Rating (CR), the area the trap affects or its attack bonus (whichever applies), the amount of damage it inflicts (in parentheses), and the DCs for saving throws or skill checks to find, avoid, and/or disable the trap.

Flame Jet: CR 2; 1-ft-wide, 50-ft-long stream of flame (3d6); Reflex save (DC 13) avoids; Search (DC 25); Disable Device (DC 26).

Lightning Blast: CR 3; 5-ft-wide, 50-ft-long blast (3d6); Reflex save (DC 13) avoids; Search (DC 26); Disable Device (DC 25).

Globe of Cold: CR 4; 20-ft-radius sphere or hemisphere (5d6); Reflex save (DC is) avoids; Search (DC 27); Disable Device (DC 25).

Electrified Floor: CR4; section of floor (3d10); Reflex save (DC 14) for half damage; Search (DC 25); Disable Device (DC 25).

Floor Transforms into Acid: CR 6; section of floor (10d6);, Reflex save (DC 16) negates; Search (DC 28); Disable Device (DC 30). Note: Successful save means character dives to safety in time.

Illusion over Spiked Pit (20 Ft. deep): CR 3; no attack roll required (2d6), +10 melee (1d4 spike attacks for 1d4+2 points of damage per successful hit); Reflex save (DC 15) negates; Search (DC 20); Disable Device (DC 20).

Air Sucked out of Room: CR 5; one room (see note); Search (DC 28); Disable Device (DC 30). Note: Deals suffocation damage (see Suffocation).

Dungeon Ecology

The inhabited dungeon is an environment in and of itself. The creatures that live there need to ear, drink, breathe, and sleep just like the creatures of the forest or the plains. Predators need prey.

Creatures living in the dungeon need to be able to get around. Locked doors, or even doors that require hands to open, can prevent creatures from getting to food or water.

Consider these factors when designing a dungeon you want the players to believe in. If the environment doesn't have some logic behind it, the PCs can't make decisions based on reasoning while adventuring there. For example, upon finding a pool of fresh water in the dungeon, a character should be able to make the assumption that many of the creatures inhabiting the place come to that spot often. Thus, the PCs could wait in ambush for a particular creature that they're after. Bits of faulty dungeon logic, such as all the doors in a dungeon being locked when the dungeon is home to many creatures, destroy any chance of verisimilitude.

Dungeon Animals

Not everything that lives in a dungeon is a monster. Other creatures inhabit these unlit labyrinths as well.

Creepy Crawlers: Insects, spiders, grubs, and worms of all types live in the dark recesses of dungeons. They don't present a real threat, but they do provide food for predators and scavengers in the dungeon - who in turn pose a threat to adventurers.

Rats: Rats make up an important part of any dungeon ecology. These omnipresent vermin serve as the staple for most dungeon predators and scavengers. In huge packs, they become a threat themselves.

Bats: Like rats, bats are found throughout any dungeon with access to outside air. Although never truly dangerous, a swarm of bats can obscure vision and hamper the actions of dungeon delvers - particularly spellcasting.

Other Animals: Strange as it may sound, other animals ranging from small creatures such as badgers and ferrets to large omnivores such as bears and apes may take to a full-time (or almost full-time) subterranean existence in a world filled with dungeons and caverns. Predatory animals such as tigers, wolves, and snakes follow their prey down into the dungeons and remain, becoming a part of the ecology. Deep dungeon delvers have brought back stories of colossal caverns far underground with flocks of birds flying about. And of course underground streams, lakes, and even seas, teem with all sorts of fish, water mammals, and aquatic reptiles.

Over the generations, dungeon animals have developed darkvision in order to survive. They adapted to their environment, and now they thrive in the dark confines of caves and passages. They feed on mold, fungi, or each other. Because of the lack of sunlight, many species have become entirely white, while others have evolved a black coloration to hide in the darkness.

Dungeon Slimes, Molds, and Fungi

In a dungeon's damp, dark recesses, molds and fungi thrive. While some plants and fungi are monsters (see the Monster Manual), and other slime, mold, and fungus is just normal, innocuous stuff, a few varieties are dangerous dungeon encounters. For purposes of spells and other special effects, all slimes, molds, and fungi are treated as plants. Like traps, dangerous shines and molds have CRs, and characters earn XP for encountering them.

Green Slime (CR 4)

Glistening organic sludge coats almost anything that remains in the damp and dark for too long, but green slime is a dangerous variety of this normal slime. Green slime devours flesh and organic materials on contact, and is even capable of dissolving metal. Bright green, wet, and sticky, it clings to walls, floors, and ceilings in patches, reproducing as it consumes organic matter. It drops from walls and, ceilings when it detects movement (and possible food) below.

A single patch of green slime deals 1d6 points of temporary Constitution damage per round while it devours flesh. On the first round of contact, the slime can be scraped off a creature (most likely destroying the scraping device), but after that it must be frozen, burned, or cur away (applying damage to the victim as well). Extreme cold or heat, sunlight, or a cure disease spell destroys a patch of green slime. Against wood or metal, green slime deals 2d6 points of damage per round, ignoring metal's hardness but not that of wood. It does nor harm stone.

Dwarves consider green slime to be one of the worst hazards of mining and underground construction. They have their own ways of burning it out of infested areas, methods that they say are thorough. "If you don't do it right, the stuff comes right back," they claim.

Mold and Fungus

Molds and fungi flourish in dark, cool, damp places. While some are as inoffensive as the normal dungeon slime, others are quite dangerous. Mushrooms, puffballs, yeasts, mildew, and other sorts of bulbous, fibrous, or flat patches of fungi can be found throughout most dungeons. They are usually inoffensive and some are even edible (though most are unappealing or odd-tasting).

Yellow Mold (CR 6): if disturbed, a patch of this mold bursts forth with a cloud of poisonous spores. All within 10 feet of the mold must make a Fortitude save (DC 15) or take 1d6 points of temporary Constitution damage. Another Fortitude save (DC is) is required 1 minute later - even by those who succeeded at the first save - to avoid taking 2d6 points of temporary Constitution damage. Fire destroys yellow mold, and sunlight renders it dormant.

Brown Mold (CR 2): Brown mold feeds on warmth, drawing heat from anything around it. It normally comes in patches 2 to 3 feet in diameter, and the temperature is always cold in the area surrounding it. Living creatures within 5 feet of it take 3d6 points of cold subdual damage. Fire brought within 5 feet of the mold causes it to instantly double in size. Cold damage, such as from a cone of cold, instantly destroys it.

Phosphorescent Fungus (No CR): This strange underground fungus grows in patches that look almost like stunted shrubbery. It gives off a soft violet glow that illuminates underground caverns and passages. Drow cultivate it for food and light.

Wandering Monsters

While the adventurers are exploring the dungeon, the light of their lanterns attracts the attention of hungry dire weasels, who come to see if they can catch some soft and juicy things to eat. On another delve, a carrion crawler finds them and follows behind, them, out of sight. When it hears a fight, it scrambles up from behind and tries to make off with a character who has fallen in combat. On yet another expedition, the party meets another party of adventurers. If the two groups can work together, they can exchange vital information, trade valuable items, and possibly even work together. The meeting, however, could just as easily turn into a nasty fight. Wandering monsters such as these add unpredictability and action to dungeon adventures.

Wandering Monster Rolls

As the adventurers explore a dungeon, make wandering monster rolls to see if they encounter wandering monsters. Use wandering monster rolls to add an unpredictable element to a dungeon delve, to encourage characters to keep moving, and to put a price on being noisy. The exact formula for when you roll for wandering monsters is up to you. Generally, there is a 10% chance for a wandering monster to show up in certain conditions.

Wandering Monster Summary

Wandering Monster Chance = 10%

Make a wandering monster roll on d% in the following circumstances:

You may decide to add or omit rolls in the following circumstances:

When a Certain Amount of Time Has Passed: Making one roll per hour is typical. You can roll more often in heavily populated areas, up to as often as once per every 10 minutes. If you're not already tracking time in the dungeon and you don't want to start, roll for wandering monsters when the characters are doing anything that takes a long time (such as taking 20 while searching a room for secret doors) instead of by the clock.

When Characters Make Noise: Breaking a door or having a typical fight counts as making noise. Breaking a door and then having a fight right away counts as one instance of noise, so it's one roll. Getting into a loud argument, knocking over a statue, and running up and down stairs in full kit at top speed are other actions that might call for a wandering monster roll.

In High-Traffic Areas: Deciding what constitutes a high-traffic area is up to you. You can roll every time the characters enter a new large corridor, provided those corridors make it easy for creatures to get to and fro and thus have a lot of traffic. Other areas, such as pools of fresh water, might also attract many creatures.

In Cleared-Out Areas: If the PCs have cleared out part of the dungeon, then you can roll for wandering monsters as they travel through a cleated area to an uncleared area. After all, creatures spread out to fill a vacuum, claiming abandoned territory as their own. These rolls reward players for staying in the dungeon longer at a stretch rather than returning to the surface frequently to heal up. (The more often they leave and return, the more wandering monsters they face.)

When Leaving the Dungeon: While you have every right to roll for wandering monsters as the party is leaving the dungeon, you might decide not to. The characters generally make good time as they head for the surface, and they're usually taking a route they have just used on their way in, so it's reasonable for the chance for wandering monsters to go down. Also, if the players know that the characters might face an extra encounter on the way home, they tend to break off their exploration when they feel they can still handle another encounter, causing them to act more cautiously than they want to or than you may want them to.

Monsters Encountered

In a sprawling, random dungeon, you can simply use the random monster tables to determine which monsters wander by. Reroll if the result would be a stationary creature or one unlikely to wander. In a smaller or special dungeon, make your own random encounter tables.

The entries on a customized wandering monster list can indicate individual monsters or groups of monsters rather than kinds of monsters. For example, the entry "Large monstrous scorpion" could mean a particular scorpion that lives in this dungeon rather than a random scorpion from an indefinitely large population of similar scorpions. That way, once the characters have killed that scorpion, they can't encounter it again. Creatures on a customized chart could also have lairs keyed on the dungeon map, so that adventurers who kill a creature while it's wandering would later find its lair empty Similarly, those who kill it in its lair would never encounter it wandering.

In the same way that you can invent the denizens of specific dungeon rooms rather than determining them randomly, you can invent specific wandering monsters. These could include monsters that escaped from the PCs before (or that the PCs escaped from). Indeed, you can replace the idea of the wandering monster with a random event instead. The characters could hear fighting in the distance, stumble across random clues to the dungeon's past, or become subject to strange, fluctuating magical auras in place of encountering a wandering monster.

Wandering Monsters' Treasure

Overall, wandering monsters don't have as much treasure as monsters encountered in their lairs. When NPCs are encountered as "wandering monsters," their gear is their treasure. Intelligent wandering monsters might (50% chance) have a treasure whose level is equal to the dungeon level. Unintelligent monsters don't have treasure. A dire weasel's den might be littered with the valuables of creatures it has killed, but it doesn't carry that stuff around with it.

Since wandering monsters have less treasure than monsters in their lairs or homes, characters typically try to minimize their encounters with wandering monsters.

Lands of Faerûn