Multiattack

Three Slam attacks.

Slam

Melee Weapon Attack: +7 to hit, 5 ft., one target, 13 (2d8+4) bludgeoning damage and the target must make DC 15 Con save or be poisoned until end of its next turn.

Sewer Overflow (Recharge 5-6)

Emits a tide of filth and water from itself in a 15 ft. cube. Each creature in this cube: 18 (4d8) bludgeoning damage and 18 (4d8) poison and is infected with sewer plague (DC 15 Con half damage and isn't infected).