Medium swarm of Tiny beasts, unaligned

Armor Class 12 (natural armor)
Hit Points 22 (5d8)
Speed 20 ft., climb 20 ft.

STR	DEX	CON	INT	WIS	CHA
3 (-4)	13 (+1)	10 (+0)	1 (-5)	7 (-2)	1 (-5)

Saving Throws 
Skills 
Damage Resistances bludgeoning, piercing, slashing
Damage Immunities 
Condition Immunities charmed, frightened, grappled, paralyzed, petrified, prone, restrained, stunned
Senses blindsight 10 ft., passive Perception 8
Languages —
Challenge 44928 (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.

Variant: Insect Swarms

Different kinds of insects can gather in swarms, and each swarm has the special characteristics described below.

Swarm of Beetles. A swarm of beetles gains a burrowing speed of 5 feet.

Swarm of Centipedes. A creature reduced to 0 hit points by a swarm of centipedes is stable but poisoned for 1 hour, even after regaining hit points, and paralyzed while poisoned in this way.

Swarm of Spiders. A swarm of spiders has the following additional traits.
Spider Climb. The swarm can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.
Web Sense. While in contact with a web, the swarm knows the exact location of any other creature in contact with the same web. Web Walker. The swarm ignores movement restrictions caused by webbing.

Swarm of Wasps. A swarm of wasps has a walking speed of 5 feet, a flying speed of 30 feet, and no climbing speed.