[Octobernomicon 2021] Ilycladian Worm

That Which Hides Among Us

James, who had always seemed so normal, passive even, picked himself up off the floor. The anger in his eyes told Amos that things had gotten out of hand. Before he could apologize, six chitinous legs thrust outward from James’s mouth, bracing themselves against his flesh, and the monstrosity inside his friend forced its way out. 

Ilycladian Worm
Ilycladian Worm by Tatan

If a paleontologist knew what to look for, they’d find evidence of ilycladian worms in the fossil record going all the way back to the formation of Earth itself. A highly adaptive species, ilycladian worms can live in even the most extreme environments. What’s more, while most species take generations to adapt, an ilycladian worm can adapt itself to a new environment in a matter of hours.

As part of this survival instinct, ilycladian worms have learned to mimic the dominant species in their area. Over the eons, this has been dinosaurs, sharks, mammoths — even human beings. In fact, since the Neolithic era, most ilycladian worms have disguised themselves as humans. Unlike most mimics, however, ilycladian worms don’t just use color or subtle shapes to look similar to what they’re mimicking. Instead, they envelope themselves in an exosheath that is indistinguishable from the real thing. They move, eat, bleed, and even talk or sing exactly like what they’re pretending to be. 

When the ilycladian worm attacks, it starts by extending six legs out its exosheath’s mouth. It will then use those as leverage to force its first segment out. Once the first segment is out, the next set of legs will force themselves through the exosheath’s mouth, slot themselves into channels in the first set of legs, and force the next segment out. This process repeats until the worm has essentially turned itself inside out, revealing a multi-segmented creature with hinged legs and razor-filled mouths encircling each hard-shelled segment of its body. Stretched to its full length, a full-grown ilycladian worm can be more than twenty feet long and up to a foot in diameter. The exosheath, superfluous in this form, is stored in a chitinous shell at the very tip of the worm’s body. 

Ilycladian worms are astonishingly fast and will devour even the largest prey with a speed and ferocity that makes piranha look like goldfish.

To resume their mimic form, the worm simply reverses the process, pulling its exosheath over its segments one by one, arranging itself carefully inside, until it’s completely covered with its disguise again.


Mimicry: An ilycladian worm can grow an exosheath to exactly duplicate any living creature

Rapid Adaptation: An ilycladian worm can develop the necessary biological mechanisms to survive in a new environment within 1d10 hours

Tough to Kill: Because of its segmented biology, even if the ilycladian worm is cut apart, the segment with the head will survive, be able to attack, and regrow itself over time. If not reduced to 0 HP, regenerate 1d6 HP per round.

Spells: None


STR: 20  

CON: 24

DEX: 26

INT: 15

POW: 12

HP:  22

Damage Bonus: +3

WP: 12


Attacks per round: 3 (1 while in “mimic form”)

Wrap attack: 65%, 1d8+3 The ilycladian worm wraps itself around its prey, interlocking its legs to keep from being dislodged while devouring its prey with the maws on its segments.

Tail whip: 50%, 1D6+3 Braces against the ground or another nearby object and slams the other end of its body into the enemy

Dodge: 60%

Armor: 8 pts of chitinous armor.

Skills: Alertness 50%, Insight 50%, Search 40%, Stealth 70%, Survival 70%, Swim 40%, other skills as decided by the GM depending on what or who the ilycladian worm is mimicking
SanityLoss: 1D4/1D8 to see an ilycladian worm emerge from its mimicry exosheath; 1/1D4 to see an ilycladian worm already out of its mimicry exosheath

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