Gutworm (CR 1/8)

Tiny Outsider (Chaotic, Evil, Extraplanar, and Symbiont)
Alignment: Always chaotic evil
Initiative: -3 (Dex); Senses: darkvision 60 ft., Listen +6, and Spot +6
Languages: Telepathy to host


AC: 10 (+2 size, -3 Dex, +1 natural), touch 9, flat-footed 10
Hit Dice: 1d8+1 (5 hp)
Fort +3, Ref -1, Will +2
Speed: 5 ft.
Space: 2 1/2 ft./0 ft.
Base Attack +1; Grapple -10
Attack: -
Full Attack: -
Damage: -
Special Attacks/Actions: -
Abilities: Str 4, Dex 5, Con 12, Int 5, Wis 10, Cha 7 (Ego: 9)
Special Qualities: enhance Constitution, incite rage, infect, neutralize poison, outsider traits, symbiont traits
Feats: Alertness
Skills: Hide +9, Listen +6, Move Silently +1, and Spot +6
Advancement: -
Climate/Terrain: Any land and underground (Abyss)
Organization: Solitary (symbiont)
Treasure: -

Source: Fiend Folio

Enhance Constitution (Ex): A creature with a gutworm symbiont gains a +2 inherent bonus to its Constitution score.

Incite Rage (Ex): At will, a gutworm can cause its host creature to enter a frenzied state identical to a barbarian's rage (+4 Strength, +4 Constitution, +2 morale bonus on Will saves, -2 AC penalty). The rage lasts 4 rounds, and the host is not fatigued afterward.

Infect (Ex): Gutworm eggs are often found in the polluted water of the Abyss and infect creatures that drink the water. A purify water spell does not remove the eggs from the water, although they die if left in pure water for one day. Once inside a host, the eggs hatch in 1d4 hours, and the spawn set about devouring one another until only one remains. A remove disease spell cast on the host kills a gutworm, but the host takes 4d6 points of damage from the creature's death throes. A creature with a gutworm must ear twice as much food as it normally requires each day, and must start making daily Constitution checks after only one day without food (instead of the normal three days). In addition, the host creature is fatigued after 8 hours of activity and takes a -4 penalty on the following checks and saves: Swim checks to resist subdual damage; Constitution checks to continue running, to avoid subdual damage from a forced march, to hold its breath, or to avoid subdual damage from starvation or thirst; and Fortitude saves to avoid subdual damage from hot or cold environments, or to resist damage from oxygen deprivation.

Neutralize Poison (Su): Once per day, a gutworm can negate any poison introduced into its host's body (not just ingested poisons), protecting its host from any ill effects.

Outsider Traits: A fiendish symbiont has darkvision (60-foot range). It cannot be raised or resurrected (though a wish or miracle spell can restore life).

Telepathy (Su): A fiendish symbiont can communicate telepathically with its host creature, if the host has a language.

Symbiont Traits: When joined with a host, a symbiont gains a number of benefits. It acts on its host's turn each round, regardless of its own initiative modifier. It is not flat-footed unless its host is, and it is aware of any danger its host is aware of.

A symbiont never takes damage from attacks directed at the host. Like a worn magic item, a symbiont is usually unaffected by spells that damage the host, but if the host rolls a 1 on its saving throw, the symbiont is one of the "items" that can be affected by the spell. A symbiont uses its host's base saving throw bonuses if they are better than its own.

Share Spells (Su): Any spell the host creature casts on itself automatically also affects the symbiont. Additionally, the host may cast a spell with a target of "Self" on the symbiont instead of on itself. Likewise, a symbiont can choose to have any spell or spell-like ability it uses on itself also affect the host creature, and may cast a spell with a target of "Self" on its host instead of on itself. The host and symbiont can share spells even if the spells normally do not affect creatures of the host or symbiont's type. Spells targeted on the host by another spellcaster do not affect the symbiont, and vice versa.

Chaotic Subtype

A subtype usually applied only to outsiders native to the chaotic-aligned Outer Planes. Most creatures that have this subtype also have chaotic alignments; however, if their alignments change they still retain the subtype. Any effect that depends on alignment affects a creature with this subtype as if the creature has a chaotic alignment, no matter what its alignment actually is. The creature also suffers effects according to its actual alignment. A creature with the chaotic subtype overcomes damage reduction as if its natural weapons and any weapons it wields were chaotic-aligned (see Damage Reduction).

Evil Subtype

A subtype usually applied only to outsiders native to the evil-aligned Outer Planes. Evil outsiders are also called fiends. Most creatures that have this subtype also have evil alignments; however, if their alignments change, they still retain the subtype. Any effect that depends on alignment affects a creature with this subtype as if the creature has an evil alignment, no matter what its alignment actually is. The creature also suffers effects according to its actual alignment. A creature with the evil subtype overcomes damage reduction as if its natural weapons and any weapons it wields were evil-aligned (see Damage Reduction).

Extraplanar Subtype

A subtype applied to any creature when it is on a plane other than its native plane. A creature that travels the planes can gain or lose this subtype as it goes from plane to plane. This book assumes that encounters with creatures take place on the Material Plane, and every creature whose native plane is not the Material Plane has the extraplanar subtype (but would not have when on its home plane). An extraplanar creatures usually has a home plane mentioned in its description. These home planes are taken from the Great Wheel cosmology of the D&D game (see Chapter 5 of the Dungeon Master's Guide). If your campaign uses a different cosmology, you will need to assign different home planes to extraplanar creatures.

Creatures not labeled as extraplanar are natives of the Material Plane, and they gain the extraplanar subtype if they leave the Material Plane. No creature has the extraplanar subtype when it is on a transitive plane; the transitive planes in the D&D cosmology are the Astral Plane, the Ethereal Plane, and the Plane of Shadow.