Shedinja (5e Creature)
From D&D Wiki
Small undead, any alignment
Avoidance. If the shendinja is subjected to an effect that allows it to make a saving throw to take only half damage, it instead takes no damage if it succeeds on the saving throw, and only half damage if it fails.
Wonder Guard. The shedinja is immune to damage from all attacks, unless the attack is a critical hit. In addition, it has advantage on all saving throws, and takes no damage from magic missile.
X-Scissor. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 12 (2d8 + 3) slashing damage.