Medium swarm of Tiny beasts, unaligned

Armor Class 12
Hit Points 22 (5d8)
Speed 0 ft., fly 30 ft.

STR	DEX	CON	INT	WIS	CHA
5 (-3)	15 (+2)	10 (+0)	2 (-4)	12 (+1)	4 (-3)

Saving Throws 
Skills 
Damage Resistances bludgeoning, piercing, slashing
Damage Immunities 
Condition Immunities charmed, frightened, grappled, paralyzed, petrified, prone, restrained, stunned
Senses blindsight 60 ft., passive Perception 11
Languages --
Challenge 44930 (50 XP)

Echolocation. The swarm can’t use its blindsight while deafened.

Keen Hearing. The swarm has advantage on Wisdom (Perception) checks that rely on hearing.

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 bat. The swarm can’t regain hit points or gain temporary hit points.

Actions

Bites. Melee Weapon Attack: +4 to hit, reach 0 ft., one creature in the swarm’s space. Hit: 5 (2d4) piercing damage, or 2 (1d4) piercing damage if the swarm has half of its hit points or fewer.