Purple Worm

The purple worm can burrow through solid rock at half its burrow speed and leaves a 10-foot-diameter tunnel in its wake.

The purple worm makes one Bite attack and one Tail Stinger attack.

Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 22 (3d8 + 9) piercing damage. If the target is a Large or smaller creature, it has the Grappled condition (escape DC 19) and the Restrained condition until the grapple ends.

Melee Weapon Attack: +14 to hit, reach 10 ft., one creature. Hit: 19 (2d6 + 9) piercing damage plus 35 (10d6) poison damage.

Strength Saving Throw: DC 19, one Large or smaller creature Grappled by the purple worm (it can have up to three creatures swallowed at a time). Failure: The target is swallowed by the purple worm, and the Grappled conditions end. A swallowed creature has the Blinded and Restrained conditions, has Total Cover against attacks and other effects outside the purple worm, and takes 21 (5d6) acid damage at the start of each of the purple worm's turns. If the purple worm takes 30 damage or more on a single turn from a creature inside it, the purple worm must succeed on a Constitution saving throw (DC 19) at the end of that turn or regurgitate all swallowed creatures, each of which falls in a space within 5 feet of the purple worm and has the Prone condition. If the purple worm dies, any swallowed creature no longer has the Restrained condition and can escape from the corpse by using 20 feet of movement, exiting Prone.