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Giant Caterpillar

By Didier Descouens - Own work, CC BY-SA 4.0,, Giant Caterpillar
By Didier Descouens – Own work, CC BY-SA 4.0,

What appeared to be a large green branch begins to undulate, reveling a mammoth caterpillar.

Originally Posted by Shade of the En World forums.

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Giant caterpillars are the larval forms of giant moths. Like their mundane cousins, they come in a variety of colors and appearances, but utilize the basic statistics above.

Some giant caterpillars have been known to associate with giant ants for their mutual protection, communicating via vibrations and phenomes. Formians are known to utilize giant caterpillars as mounts, and tools to aid in construction and destruction.

Because of their great size and appetites, giant caterpillars can become extremely disruptive to farms and creatures who make their homes in trees.

A giant caterpillar is 15 feet long and weighs around 7,000 pounds. Coloration and appearance can vary greatly depending upon habitat.

Caterpillar, Giant
Huge vermin
Hit Dice13d8+39 (97 hp)
Speed20 ft. (4 squares), Climb 20 ft.
Armor Class13 (-2 size, +5 natural), touch 8, flat-footed 13
Base Attack/Grapple+9/+23
AttackBite +13 melee (2d6+9)
Full AttackBite +13 melee (2d6+9)
Space/Reach15 ft./10 ft.
Special AttacksAcid spittle
Special QualitiesDarkvision 60 ft., tremorsense 60 ft., vermin traits
SavesFort +11, Ref +4, Will +4
AbilitiesStrength 22, Dexterity 11, Constitution 16, Intelligence —, Wisdom 11, Charisma 2
SkillsClimb +14, Hide +0*, Spot +4
EnvironmentTemperate forests
OrganizationSolitary or cluster (1d6)
Challenge Rating5
AlignmentAlways neutral
Advancement14-26 HD (Huge), 27-39 HD (Gargantuan), 40+ (Colossal)
Level Adjustment


Giant caterpillars are non-aggressive, but can defend themselves with a powerful bite or by spitting acid. Some species have developed more deadly defenses (see Variants, below).

Acid Spittle (Ex): Once ever 1d4 rounds, a giant caterpillar may expel a globule of acidic spittle. This requires a ranged touch attack with a maximum range of 40 feet and no range increments, and deals 2d6 points of acid damage.

Skills: A giant caterpillar has a +4 racial bonus on Spot checks, a +8 racial bonus on Climb and Hide checks. A giant caterpillar can always choose to take 10 on Climb checks, even if rushed or threatened. *Because of its camouflage, the Hide bonus increases to +12 when a giant caterpillar is surrounded by foliage.


Like their non-giant cousins, giant caterpillars come in many varieties. Here are a few possible additional abilities to add.

Cocooning Spittle (Ex): A giant caterpillar with this ability can eject a stream of spittle that hardens on contact, potentially fixing a subject in place and hindering its movement and actions. Using a standard action, the caterpillar makes a ranged touch attack against any foe it can see up to 60 feet away. If it succeeds at the ranged touch attack, the subject makes a grapple check against the cocoon. This is accomplished as if the caterpillar itself were making the grapple check with a competence bonus of +10, for a total check modifier of +33. On a failed check for the subject, the spittle hardens into a partial cocoon, and the victim is treated as if grappled (even though the caterpillar is free to do as it desires). The subject can attempt to break the grapple of the cocoon (or use Escape Artist) each round, making an opposed grapple check against the cocoon (check modifier +33 for the cocoon). Alternatively, the cocoon may be broken with a DC 19 Strength check. The check DC is Constitution-based. This ability replaces the acidic spittle.

Poison Hairs (Ex): Any creature striking a giant caterpillar with hand-held weapons or natural weapons takes 1d4 points of piercing and slashing damage from the caterpillar’s spiny bristles. This also exposes the attacker to an injury poison (Fort DC 19, 1d3 Dexterity/1d3 Dexterity). Note that weapons with exceptional reach, such as longspears, do not endanger their users in this way. The save DC is Constitution-based. This ability increases the giant caterpillar’s CR by 1.

Poison Flesh (Ex): Ingested, Fort DC 19, 1d6 Constitution/1d6 Constitution. The save DC is Constitution-based.

Spit Hairs (Ex): Once every 1d4 rounds, this variant may spit a 30-foot cone of millions of tiny, irritating hairs. This attack deals 2d6 points of piercing damage and leaves the victim sickened for 1d4 rounds. A successful DC 19 Reflex save halves the damage and negates the sickened effect. The save DC is Constitution-based. This ability replaces the acidic spittle.

Stench (Ex): When a giant caterpillar is angry or frightened, it secretes an oily, musk-like chemical that nearly every form of animal life finds offensive. All living creatures (except giant caterpillars) within 30 feet of a giant caterpillar must succeed on a DC 19 Fortitude save or be sickened for 10 rounds. The save DC is Constitution-based. Creatures that successfully save cannot be affected by the same giant caterpillar’s stench for 24 hours. A delay poison or Neutralize poison spell removes the effect from the sickened creature. Creatures with immunity to poison are unaffected, and creatures resistant to poison receive their normal bonus on their saving throws. This ability increases the giant caterpillar’s CR by 1.

Originally appeared in Adventure Pack I (1987).

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