Swarm of Bats

Medium swarm of Tiny beasts, unaligned

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

AC	HP	CR	Prof.
12	22 (5d8)	1/4	+2

Speed 0 ft., fly 30 ft.
Damage resistances bludgeoning, piercing, slashing
Condition immunities Charmed, Frightened, Grappled, Paralyzed, Petrified, Prone, Restrained, Stunned
Senses blindsight 60 ft., passive perception 11
Languages --

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.