Ankheg A5E

Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 12 (2d8 + 3) slashing damage. If the target is a Medium or smaller creature it is grappled (escape DC 13). Until this grapple ends the target is restrained and the ankheg can't use its claws on anyone else.

Melee Weapon Attack: +5 to hit, reach 5 ft., one creature grappled by the ankheg. Hit: 16 (3d8 + 3) slashing damage. If this damage kills the target the ankheg severs its head.

The ankheg spits a 30-foot-long 5-foot-wide stream of acid. Each creature in the area makes a DC 13 Dexterity saving throw taking 14 (4d6) acid damage on a failure or half damage on a success. If the ankheg is grappling a target it instead bathes the target in acid dealing 14 (4d6) acid damage with no saving throw only to that target.