Corpse Flood

Engulf. The flood moves up to its speed. While doing so, it can enter Large or smaller creatures’ spaces. Whenever the flood enters a creature’s space, the creature must make a DC 15 Dexterity saving throw. On a successful save, the creature can choose to be pushed 5 feet back or to the side of the flood. A creature that chooses not to be pushed suffers the consequences of a failed saving throw. On a failed save, the flood enters the creature’s space, and the creature takes 10 (5d6) necrotic damage and is engulfed.The engulfed creature can’t breathe, is restrained, and takes 21 (10d6) necrotic damage at the start of each of the flood’s turns. When the flood moves, the engulfed creature moves with it. An engulfed creature can try to escape by taking an action to make a DC 15 Strength check. On a success, the creature escapes and enters a space of its choice within 5 feet of the flood. 

Voracious Growth. If a target dies due to being engulfed the flood gains 10 max HP and heals 10 HP.