Flutterflesh

Merciful Exchange. If the flutterflesh reduces a creature to 0 hp with a melee attack, it can cut off one of the creature's limbs. If it does so, the target is reduced to 1 hp instead.

Necrotic Weapons. The flutterflesh's weapon attacks are magical. When the flutterflesh hits with any weapon, the weapon deals an extra 2d8 necrotic damage (included in the attack).

Regeneration. The flutterflesh regains 10 hp at the start of its turn. If the flutterflesh takes fire or radiant damage, this trait doesn't function at the start of the flutterflesh's next turn. The flutterflesh dies only if it starts its turn with 0 hp and doesn't regenerate.

Turn Resistance. The flutterflesh has advantage on saving throws against any effect that turns undead.

Undead Nature. The flutterflesh doesn't require air, food, drink, or sleep.

Multiattack. The flutterflesh makes three Bone Spur or Tormenting Gaze attacks. If two Tormenting Gaze attacks hit one creature, the target must succeed on a DC 16 Wisdom saving throw or be paralyzed for 1 minute. A paralyzed creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Bone Spur. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 17 (2d12 + 4) piercing damage plus 9 (2d8) necrotic damage, and the flutterflesh impales the target on one of its bone spurs, grappling the target (escape DC 16). The flutterflesh can have no more than two creatures impaled at a time.

Tormenting Gaze. Ranged Spell Attack: +7 to hit, range 120 ft., one creature. Hit: 21 (4d8 + 3) psychic damage.

Creeping Death (Recharge 5-6). The flutterflesh emits a wave of necromantic energy, hastening the journey toward death. Each creature within 20 feet of the flutterflesh must make a DC 16 Constitution saving throw, taking 45 (10d8) necrotic damage on a failed save, or half as much damage on a successful one. A creature below half its hp maximum has disadvantage on this saving throw.