Hellgrammite, Giant

More than a dozen segmented black legs propel this giant, caterpillar-like insect, its thick head dominated by a pair of powerful, gnashing pincers.

Giant Hellgrammite CR 5

XP 1,600
N Large vermin (aquatic)
Init +0; Senses darkvision 60 ft., Perception +5


AC 16, touch 9, flat-footed 16 (+7 natural, –1 size)
hp 52 (7d8+21)
Fort +8, Ref +2, Will +1
Immune mind-affecting effects


Speed 30 ft., swim 20 ft.
Melee bite +8 (2d8+4 plus grab), tail slap +3 (1d8+2)
Space 10 ft.; Reach 10 ft.
Special Attacks death grip, constrict (2d8+4)


The giant hellgrammite is a simple but ferocious predator. It latches onto its prey with its deadly jaws and proceeds to crush the life from it, feeding on the body after its victim can no longer struggle. The hellgrammite often attempts to drag the prey back to a protected area between or behind stream boulders, or down to the bottom of a deep side-pool. The strength of a hellgrammite’s jaws is so great that, even in death, they clench tightly and do not relinquish their grip.


Str 19, Dex 11, Con 16, Int —, Wis 9, Cha 2
Base Atk +5; CMB +10 (+14 grapple); CMD 20 (28 vs. trip)
Skills* Climb +8, Perception +5 (+9 in water), Stealth +1 (+9 in water), Swim +7; Racial Modifiers +4 Perception (+8 in water), +8 Stealth in water
SQ amphibious


Death Grip (Ex)

Upon its death, a hellgrammite’s massive jaws close tightly and lock. Any creature or object that is grappled at the time of the hellgrammite’s death takes an additional 1d8+2 points of damage per round unless it makes a DC 22 Escape Artist check, makes a DC 20 Strength check, or deals an additional 10 points of damage to the hellgrammite’s corpse to escape.

A non-giant Hellgrammite (Dobsonfly Larva)

Source Wikipedia

Editor’s Note

Skills line seem to contain errors (Skills are off as creature is mindless). Corrected lines appear below:
Skills Climb +4, Perception +3 (+7 in water), Stealth -4 (+4 in water), Swim +12


Environment temperate rivers or streams
Organization solitary or pair
Treasure none

Giant hellgrammites are the fierce and predacious larvae of dobsonflies of terrifying size. While their diminutive brethren measure several inches long, the monstrous variety measure 10 feet long and weigh up to 800 pounds. The body of the giant hellgrammite is long and flattened, and generally ranges from dark brown to reddish in color. The front third of its body consists of a well-armored head and thoracic segments, with stout, segmented legs. The head possesses a fearsome set of jaws, small antennae, and a set of clustered eye spots on either side. The posterior two-thirds of the hellgrammite consist of nine densely haired abdominal segments, each with a pair of lateral filaments and gill tufts underneath for underwater breathing. The hellgrammite’s abdomen ends in pair of terminal prolegs, each with a pair of hooks, which aid the creature in climbing or anchoring itself in fast-moving currents, and can be used in a tail slap to slash at its enemies.

Section 15: Copyright Notice

Pathfinder Adventure Path #49: The Brinewall Legacy. © 2011, Paizo Publishing, LLC; Author: James Jacobs.

scroll to top