Water Form. The elemental can enter a hostile creature's space and stop there. It can move through a space as narrow as 1 inch wide without squeezing.

Multiattack. The elemental makes two slam attacks.

Slam. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) bludgeoning damage plus 4(1d8) acid damage.

Domination (Recharge 4–6). Each creature in the elemental's space must make a DC 16 Constitution saving throw. On a failure, a target takes 8 (1d8 + 4) acid damage. If it is Large or smaller, it is also restrained (escape DC 15). Until this grapple ends, the target is restrained.

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 13 (2d8 + 4) acid damage and pass a DC 16 Strength saving throw or use its reacton to make one melee attack against a creature of the elementals choice within range. 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 15 Strength and succeeding.