Swarm: The swarm can occupy another creature's space and vice versa, and the swarm can move through any opening large enough for a Tiny insect. The swarm can't regain hit points or gain temporary hit points.
Hollowing: Once the swarm has paralyzed a target, it will attempt to begin the process of taking over and hollowing the target to make a new husk. The target will take 11 (2d8 + 2) piercing damage each round that the hollowing takes place. The hollowing takes 3 (1d4 + 1) rounds to complete. Once the hollowing is complete, the target is now the new husk for the swarm. The target can only be restored with a True Resurrection or Wish spell.
Husk:
Slam: Melee Weapon Attack: +3 to hit, reach 5ft., one target. Hit: 4 (1d6 + 1) bludgeoning damage.
Swarm:
Bite: Melee Weapon Attack: +3 to hit, reach 0 ft., one target in the swarm's space. Hit: 10 (4d4) piercing damage, or 5 (2d4) piercing damage if the swarm has half of its hit points or fewer, and the target must make a DC 13 Constitution saving throw, taking 13 (3d8) poison damage on a failed save, or half as much damage on a successful one. If the poison damage reduces the target to 0 hit points, the target is stable but poisoned for 1 hour, even after regaining hit points, and is paralyzed while poisoned in this way.
Burst: If the husk takes 5 damage or more on one attack, then it will burst. The swarm of worms that were controlling the husk can then make a reaction to attack any target within 5ft of the burst husk.
Description
The Worm Husk appears on first inspection to be an undead creature, however the creature's body is merely a husk for the swarm of writhing maggots that fill the hollow cavity of the creature. The swarm of worms controls the husk's every move and will defend itself if attacked. If the husk is destroyed for any reason the swarm will ravenously search for a new host. The worm husk can be found wherever there are large congregations of corpses, such as a battlefield or disturbed crypts.