Acid Form. The elemental can move through a space as narrow as 1 inch wide without squeezing. A creature that touches the elemental or hits it with a melee attack while within 5 feet of it takes 9 (2d8) acid damage. The elemental can enter a hostile creature's space and stop there.

Multiattack. The elemental makes two touch attacks.

Touch. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) acid damage.

Whelm (Recharge 4–6). Each creature in the elemental's space must make a DC 15 Strength saving throw. On a failure, a target takes 13 (2d8 + 4) acid damage. If it is Large or smaller, it is also grappled (escape DC 14). Until this grapple ends, the target is restrained and unable to breathe unless it can breathe acid. If the saving throw is successful, the target is pushed out of the elemental's space.

The elemental can grapple one Large creature or up to two Medium or smaller creatures at one time. At the start of each of the elemental's turns, each target grappled by it takes 9 (2d8) acid damage. A creature within 5 feet of the elemental can pull a creature or object out of it by taking an action to make a DC 14 Strength and succeeding, attempting this deals 9 (2d8 ) acid damage to the creature.