Mordenkainen's tome of foes
Life Hunger. If a creature the Hungry can see regains hit points, the Hungry gains two benefits until the end of its next turn: it has advantage on attack rolls, and its bite deals an extra 22 (4d10) 4d10 necrotic damage on a hit.
Multiattack. The Hungry makes two attacks: one with its bite and one with its claws. Bite. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 8 (1d8 + 4) 3d8 piercing damage plus 13 (3d8) 3d8 necrotic damage. Claws. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 18 (4d6 + 4) 4d6+4 slashing damage. If the target is Medium or smaller, it is grappled (escape DC 16) and is restrained until the grapple ends. While grappling a creature, the Hungry can't attack with its claws.