Liquid 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. If a hostile creature enters the elemental's space or starts it's turn in it, it takes 9 (2d8) acid damage.

Acid Absorption. The elemental is immune to acid damage and instead regains hit points equal to the amount of damage it would have otherwise taken.

Acidic Body. Any creature within 5 ft. of the Elemental that touches it or hits it with a melee attack takes 9 (2d8) acid damage.

Multiattack. The elemental makes two slam attacks

Slam. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 16 (4d8 + 5) acid damage. 

Acid Splash (Recharge 6). The elemental sprays acid in a 30 foot radius. Any creature in the area must make a Constitution saving throw. On a failed save a creature takes 32 (5d12) acid damage, in addition any non-magical armour worn takes a -1 penalty to AC, and any non-magical weapon carried suffers a permanent -1 to attack rolls and damage. On a successful save, a creature takes half damage and suffers no penalties to their armour class or weapon's damage.