Blood Animus

Life Sense. The Blood Animus can sense the location of any creature within 60 feet of it, unless that creature’s type is construct or undead.

Water Form. The Blood Animus 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 Blood Animus takes cold damage, it partially freezes; its speed is reduced by 20 feet until the end of its next turn.

Fuel for the Horde: Any undead within 20 feet of the Blood Animus can not be reduced to 0 hit points.

Constant Feeding: The Blood Animus deals 10 (2d10) damage at the end of it's turn divided between targets within 20 feet, regaining health equal to the amount. (Undead and constructs are immune.)

Abandoned Attunement: If the Blood Animus has no creatures within 20 feet at the end of it's turn, the Blood Animus takes 15 (3d10) damage.

Life Drain. The Blood Animus touches one creature within 10 feet.. The target must succeed on a DC 15 Constitution saving throw (undead and constructs automatically succeed), or it takes 14 (2d8 + 6) necrotic damage, the Blood Animus regains 13 hit points, and the target’s hit point maximum is reduced by an amount equal to the necrotic damage taken. This reduction lasts until the target finishes a long rest. The target dies if its hit point maximum is reduced to 0.

Whelm (Recharge 4–6). Each creature in the Blood Animus' 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 unless it can breathe water. If the saving throw is successful, the target is pushed out of the Blood Animus's space.

The Blood Animus 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) bludgeoning 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.