Burrowing Snagret

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

Horrifying Cry. Upon the Snagret's death, it releases a ear-piercing cry. Every creature within a 10 foot radius (unless they are currently swallowed) must pass a DC 12 Constitution saving throw or take 2d4 Thunder Damage and become deafened for 10 minutes. 

Multiattack. The Snagret makes two attacks.

Peck. Melee Weapon Attack: +6 to hit, reach 10 ft., one target. Hit: 22 (3d8 + 9) piercing damage. If the target is a Large or smaller creature, it must succeed on a DC 19 Dexterity saving throw or be swallowed by the worm. A swallowed creature is blinded and restrained, it has total cover against attacks and other effects outside the worm, and it takes 8 (3d4) piercing damage at the start of each of the Snagret's turns.

If the Snagret takes 30 damage or more on a single turn from a creature inside it, the Snagret must succeed on a DC 21 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone in a space within 10 feet of the worm. If the Snagret dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 20 feet of movement, exiting prone.