Crypt Golem

Necrotic Fortitude. Whenever the golem is subject to necrotic damage, it takes no damage  and instead regains a number of hit points equal to the necrotic damage dealt. 

Decaying Corpses (2/day). On its turn as a bonus action, the Crypt Golem can detach a corpse from its torso and consume it, regaining (1d12 + 4) hit points.

Multiattack. The golem makes two slam attacks.

Slam. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: (2d8 + 5) bludgeoning damage. If the target is a creature, it must succeed on a DC 13 Wisdom saving throw or become frightened, until the end of their next turn. If the targeted creature is already frightened, they take an additional 2d4+1 damage.

Haunting Memories (Recharge 5–6) The golem emits a high pitched shriek from the many mouths of corpses that are attached to its body. Any creature in a 15 foot radius who can hear the shriek needs to make a DC 15 Charisma saving throw. Upon failure, they gain one level of exhaustion (which cannot exceed 4).