Xeg-Yi (CR 5)
AC: 17 (+3 Dex, +4 deflection), touch 17, flat-footed 14
Hit Dice: 5d8+5 (27 hp)
Fort +5, Ref +7, Will +4
Speed: Fly 20 ft. (good)
Space: 5 ft./5 ft.
Base Attack +5; Grapple +0
Attack: 4 incorporeal touches +8 melee; or negative energy ray +8 ranged touch
Full Attack: 4 incorporeal touches +8 melee; or negative energy ray +8 ranged touch
Damage: Incorporeal touch 1d6 and negative energy; negative energy ray 1d8
Abilities: Str -, Dex 17, Con 12, Int 7, Wis 10, Cha 18
Special Qualities: Incorporeal, negative energy lash, rebuke undead, explosion
Feats: Combat Reflexes; Extra Turning
Skills: Hide +10, Search +5, Sense Motive +8, and Spot +8
Advancement: 6-9 HD (Medium-size); 10-15 HD (Large)
Climate/Terrain: Any land and underground
Organization: Solitary or cluster (2-8)
Manual of the Planes
Incorporeal: Energons can be harmed only by other incorporeal creatures, +1 or better magic weapons or magic, with a 50% to chance ignore any damage from a corporeal source. They can pass through solid objects at will, and their attacks pass through armor. They always move silently.
Energy Ray (Ex): An energon's energy ray has a range of 30 feet.
Explosion (Su): If an energon is reduced to 0 hit points, its body is instantaneously destroyed in an explosion of positive or negative energy that deals 1d8+9 points of damage to everyone in a 20 foot radius burst (Fortitude save DC 16 half). If a xag-ya and xeg-yi see each other, they rush together as fast as they can. When they make contact, both creatures are destroyed in an explosion that deals 2d8+18 points of damage within a 30-foot radius (Fortitude save DC 16 half).
Negative Energy Lash (Su): A xeg-yi can make a ranged touch attack or hit with an incorporeal touch attack to infuse a target with negative energy. This deals an additional 2d8+5 points of damage to a living target but heals an undead creature by the same amount. A xeg-yi can control its negative energy enough to avoid healing an undead foe (dealing only the base damage). This power can be used up to five times per day.
Rebuke Undead (Su): A xeg-yi can flood a 60-foot-radius area with negative energy, making undead creatures cower in fear. It rebukes undead as a 5th-level cleric, doing so up to five times per day. It cannot command undead.
The Xag-Ya and Xeg-Yi first appeared in S4 The Lost Caverns of Tsojcanth (Gary Gygax, 1982).
Some creatures are incorporeal by nature, while others (such as those that become ghosts) can acquire the incorporeal subtype. An incorporeal creature has no physical body. It can be harmed only by other incorporeal creatures, magic weapons or creatures that strike as magic weapons, and spells, spell-like abilities, or supernatural abilities. It has immunity to all nonmagical attack forms. Even when hit by spells, including touch spells or magic weapons, it has a 50% chance to ignore any damage from a corporeal source (except for positive energy, negative energy, force effects such as magic missile, or attacks made with ghost touch weapons). Non-damaging spell attacks affect incorporeal creatures normally unless they require corporeal targets to function (such as the spell implosion) or they create a corporeal effect that incorporeal creatures would normally ignore (such as a web or wall of stone spell). Although it is not a magical attack, a hit with holy water has a 50% chance of affecting an incorporeal undead creature.
An incorporeal creature's natural weapons affect both in incorporeal and corporeal targets, and pass through (ignore) corporeal natural armor, armor, and shields, although deflection bonuses and force effects (such as mage armor) work normally against it. Attacks made by an incorporeal creature with a nonmagical melee weapon have no effect on corporeal targets, and any melee attack an incorporeal creature makes with a magic weapon against a corporeal target has a 50% miss chance except for attacks it makes with a ghost touch weapon, which are made normally (no miss chance).
Any equipment worn or carried by an incorporeal creature is also incorporeal as long as it remains in the creature's possession. An object that the creature relinquishes loses its incorporeal quality (and the creature loses the ability to manipulate the object). If an incorporeal creature uses a thrown weapon or a ranged weapon, the projectile becomes corporeal as soon as it is fired and can affect a corporeal target normally (no miss chance). Magic items possessed by an incorporeal creature work normally with respect to their effects on the creature or another target. Similarly, spells cast by an incorporeal creature affect corporeal creatures normally.
An incorporeal creature has no natural armor bonus but has a deflection bonus equal to its Charisma bonus (always at least +1, even if the creature's Charisma score does not normally provide a bonus).
An incorporeal creature can enter or pass through solid object but must remain adjacent to the object's exterior, and so cannot pass entirely through an object whose space is larger than its own. It can sense the presence of creatures or objects a square adjacent to its current location, but enemies have total concealment from an incorporeal creature that is inside an object. In order to see clearly and attack normally, a incorporeal creature must emerge. An incorporeal creature inside an object has total cover, but when it attacks a creature outside the object it only has cover, so a creature outside with a readied action could strike at it as it attacks. An incorporeal creature cannot pass through a force effect.
Incorporeal creatures pass through and operate in water as easily as they do in air. Incorporeal creatures cannot fall or take falling damage. Incorporeal creature cannot make trip or grapple attacks against corporeal creatures, nor can they be tripped or grappled by such creatures. In fact, they cannot take any physical action that would move or manipulate a corporeal being or its equipment, nor are they subject to such actions. Incorporeal creatures have no weight and do not set off traps that are triggered by weight.
An incorporeal creature moves silently and cannot be heard with Listen checks if it doesn't wish to be. It has no Strength score, so its Dexterity modifier applies to both its melee attacks and its ranged attacks. Non-visual senses, such as scent and blindsight, are either ineffective or only partly effective with regard to incorporeal creatures. Incorporeal creatures have an innate sense of direction and can move at full speed even when they cannot see.