Slam

Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 12 (2d8 + 3) bludgeoning damage plus 5 (2d4) poison damage.

Expel Vermin (Recharge 6)

The putrid haunt vomits forth the leeches, stinging insects, and other swamp vermin infesting its innards in a 15-foot cone. Each creature in the area must make a DC 13 Dexterity saving throw. On a failure, a creature takes 7 (2d6) piercing damage and 7 (2d6) poison damage and is poisoned for 1 minute. On a success, a creature takes half the damage and isn't poisoned. A poisoned creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.