Ayperobo Swarm

Medium swarm of tiny fiends (devil), lawful evil

Armor Class

20 (natural armor)

Hit Points

130 (20d8 + 40)

Speed

5 ft., fly 60 ft. (hover)

Saves

Dex +11, Cha +5

Skills

Intimidation +5, Perception +5, Stealth +11, Survival +5

Damage Resistances

cold; bludgeoning, piercing, and slashing from nonmagical attacks that aren't silvered

Damage Immunities

fire, poison

Condition Immunities

charmed, frightened, grappled, paralyzed, petrified, poisoned, prone, restrained, stunned

Senses

blindsight 30 ft., darkvision 120 ft.

Languages

Celestial, Draconic, Infernal, telepathy 120 ft.

Challenge

12

Proficiency Bonus

+4

Devil's Sight

Magical darkness doesn't impede the ayperobo swarm's darkvision.

Magic Resistance

The ayperobo swarm has advantage on saving throws against spells and other magical effects.

Swarm

The ayperobo swarm can occupy another creature's space and vice versa, and the swarm can move through any opening large enough for a Tiny creature. The ayperobo swarm can't regain hit points or gain temporary hit points.

Actions

Multiattack

The ayperobo swarm makes three Bite attacks.

Bite

Melee Weapon Attack: +11 to hit, reach 0 ft., one target. Hit: 27 (8d4 + 7) piercing damage, or 17 (4d4 + 7) piercing damage if the swarm has half of its hit points (65) or fewer.

Burrow (Recharge 6)

The ayperobo swarm makes a Bite attack. On a hit, the swarm burrows inside the creature, dealing an additional 35 (10d6) necrotic damage and taking control of the creature. At the start of each of its turns, the target may make a DC 17 Constitution saving throw, expelling the ayperobo swarm and taking 14 (4d6) piercing damage on a success. While burrowed inside a creature, the ayperobo swarm has total cover against attacks targeting them, and no longer acts on their own initiative. Instead, they take total control over their host, gaining all of its abilities, attacks, and equipment. They act during the host's turn, taking actions based on their host. If a host dies while the ayperobo swarm is burrowed, they leave the host at the end of the host's turn, rolling initiative if necessary. Creatures acting as hosts to the ayperobo swarm are fully aware of their actions and surroundings, but are incapable of physically operating their body.