Blood Boil

Blood Frenzy. The Blood Boil has advantage on melee attacks against any creature that doesn't have all of its hit points.

Heated Body. A creature that touches the Blood Boil or hits it with a melee attack while within 5 feet of it takes 2 (1d4) fire damage.

Pseudopod. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 2) bludgeoning damage plus 2 (1d4) fire damage.

Blood Drain. Melee Weapon Attack: +4 to hit, reach 5 ft., one creature. Hit: 4 (1d4 + 2) piercing damage, and the target is grappled (escape dc 12). Until this grapple ends, the blood boil can't use its pseudopods on another target.
At the start of each of the Blood Boil's turns, the target loses 4 (1d4 + 2) Hit Points due to blood loss. The Blood Boil regains hit points equal to the amount of damage it deals in this way. If the Blood Boil's hit points are at maximum, regained hit points are instead added as temporary hit points.
The Blood Boil can detach itself by spending 5 feet of its Movement. It does so after the target dies.