Medium swarm of Tiny beasts, unaligned

Armor Class 12
Hit Points 22 (5d8)
Speed 5 ft., fly 30 ft.

Damage Resistances bludgeoning, piercing, slashing
Condition Immunities charmed, frightened, grappled, paralyzed, petrified, prone, restrained, stunned
Languages —
Challenge 1/2 (100 XP)

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

Actions

Bites. Melee Weapon Attack: +3 to hit, reach 0 ft., one target in the swarm’s space. Hit: 10 (4d4) piercing damage, or 5 (2d4) piercing damage if the swarm has half of its hit points or fewer.