Swarm of Insects

Medium Beast, Unaligned

AC: 11

Initiative: +1 (11)

HP: 19 (3d8 + 6)

Speed: 20 ft., 20 ft. (climb or fly; (DM's choice))

STR
3 (-4)
DEX
13 (+1)
CON
14 (+2)
INT
1 (-5)
WIS
7 (-2)
CHA
1 (-5)

Resistances: bludgeoning; piercing; slashing

Condition Immunities: charmed; frightened; grappled; paralyzed; petrified; prone; restrained; stunned

Senses: Blindsight 30 ft., Passive Perception 8

CR: 1/2 (XP 100; PB +2)

Habitat: Desert, Forest, Grassland, Hill, Swamp, Underdark, Urban

Spider Climb.

If the swarm has a Climb Speed, the swarm can climb difficult surfaces, including along ceilings, without needing to make an ability check.

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 Attack Roll: +3, reach 5 ft. Hit: 6 (2d4 + 1) Poison damage, or 3 (1d4 + 1) Poison damage if the swarm is Bloodied.

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Swarm of Insects

Source: Monster Manual (2025), p. 370 - Licenses and attribution