Blood Elemental

Blood 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.

Freeze. If the elemental takes cold damage, it partially freezes; its speed is reduced to 20 feet until the end of its next turn.

Regeneration. The elemental regains 10 hit points at the start of its turn if it has at least 1 hit point. If the elemental takes cold damage, this trait doesn’t function at the start of the elemental’s next turn.

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.

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) bludgeoning 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. 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 with this ability. At the start of each of the elemental’s turns, each grappled target takes 13 (2d8 + 4) bludgeoning damage. As an action, a creature within 5 feet of the elemental can pull a creature or an object out of it by succeeding on a DC 14 Strength check.