Worm That Walks

For it is of old rumour that the soul of the devil-bought hastes not from his charnel clay, but fats and instructs the very worm that gnaws; till out of corruption horrid life springs, and the dull scavengers of earth wax crafty to vex it and swell monstrous to plague it. Great holes secretly are digged where earth’s pores ought to suffice, and things have learnt to walk that ought to crawl.” -H.P. Lovecraft, The Festival

A Worm That Walks is a swarm of vermin assembled into a coherent humanoid mass that shares a single intelligence, retaining memories of its host's devoured corpse and seeking to continue the creature’s dark schemes or to seek revenge against those who slew it.

A Worm That Walks reproduces by first slaying a worthy creature such as a powerful spellcaster or warrior. Rather than consuming the body, the swarm divides itself, filling the corpse with scores of its component creatures. Over time, these vermin devour the corpse and arise as a new Worm That Walks. This newborn monster gains much of the victim's memories and knowledge in the process.

Worm That Walks Template

A beast, humanoid, fey, giant, monstrosity, or undead can become a Worm That Walks. The nature of the Worm That Walks is such that the template is most effective when the host has some type of gaze or fear effect, to enforce the horror of the creature's existence. When a creature becomes a Worm That Walks, it retains all its statistics except as noted below.

Type. The creature type changes to Swarm of Tiny undead.

Resistances. The Worm that Walks gains resistance to bludgeoning, piercing, and slashing damage.

Immunities. The Worm that Walks gains immunity to poison damage and the charmed, frightened, paralyzed, petrified, poisoned, prone, restrained, and stunned conditions.

Senses. The Worm that Walks gains blindsight with a radius of 10 feet and darkvision with a radius of 60 feet.

New Trait: Swarm. The Worm that Walks can move through any opening large enough for a Tiny creature. The Worm That Walks can't regain hit points or gain temporary hit points.

New Action: Shifting Swarm. The Worm that Walks can Dash, Disengage, or Hide as a bonus action.

Optional Trait: Insect Swarm. A Worm that Walks often assumes a swarm of worms, grubs, or maggots, but might instead take a different form. These swarms can have special characteristics such as those as described in the

Insect Swarm sidebar on Monster Manual pg 338.

Challenge Rating. If the base creature's challenge rating was 10 or lower, increase the challenge by 1 and adjust the XP reward as necessary.

Sample Worms That Walk

Here the template has been applied to four different creatures: a Sea Hag to create a Brood Hag, a Mummy to create a Scarab Mummy, a Fomorian to create a Wormspawn Praetorian, and to a Lich to create a Larva Mage.

Adaptation by Peter "Galemp" Oliver