Bevinget

Innate Spellcasting. The Bevinget innate spellcasting ability is Charisma. The Bevinget can innately cast the following spells, requiring no material components:

At will: darkness, detect magic, dispel magic, invisibility (self only), mirror image

Magic Resistance. The Bevinget has advantage on saving throws against spells and other magical effects.

Magic Weapons. The Bevinget  weapon attacks are magical.

Hive Mind. The swarm hold's their action until last in initiative so they can attack at once with the same attack.

Multiattack. The Bevinget makes two melee attacks, or it makes one melee attack and teleports before or after the attack.

Claw. Melee Weapon Attack: +9to hit, reach 5 ft., one target. Hit: 12 (2d6 + 5) slashing damage. If the target is a creature, it must succeed on a DC 16 Constitution saving throw or take 5 (2d4)slashing damage at the start of each of its turns due to a fiendish wound. Each time the Bevinget hits the wounded target with this attack, the damage dealt by the wound increases by 5 (2d4). Any creature can take an action to stanch the wound with a successful DC 13 Wisdom (Medicine) check. The wound also closes if the target receives magical healing.

Teleport. The Bevinget magically teleports, along with any equipment it is wearing or carrying, up to 60 feet to an unoccupied space it can see.