Multiattack. make one bite and one tail stinger attack
Bite. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 22 (3d8 +9) piercing damage. Target must make DC 19 dexterity saving throw or be swallowed, if size large or smaller. While inside blinded, restrained, and total cover from outside attacks. Suffers 21 (6d6) acid damage at start of turn. If damage taken by worm is 30 or more on a single turn the worm must make a DC 21 Constitution saving throw or regurgitate swallowed creatures.
Tail Stinger. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 19 (3d6 + 9) piercing damage. Target must make a DC 19 constitution saving throw or take 42 (12d6) poison damage on a failed save, half damage on success.