W.O.R.M

Grapple. Opposed athletics, reach 10 ft., one target.

Mace. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 2) bludgeoning damage.

Tentacle. Melee Weapon Attack: +4 to hit, reach 10 ft., one target. Hit: 4 (1d4+2) bludgeoning damage. The target must make a DC 10 constitution saving throw, taking 3 (1d6) poison damage on a fail (or half as much if they succeed).

Burrow. The W.O.R.M can use its bonus action each turn to burrow into the ground, or exit its burrow.

Shapechanger. The W.O.R.M can use its action to polymorph into a monstrosity-humanoid hybrid, or back into its true form, which is humanoid. Its statistics are the same in each form. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.

Self Destruct. When the W.O.R.M falls to 0 hit points it can use its reaction to detonate an acid bomb centered on itself. Creatures withing 10 ft. must make a DC 11 Dex save or take 6 (2d6) acid damage on a failed save.