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Swarm of Beetles 5e: Stats, Burrowing and Running the Swarm
A swarm of beetles is a CR 1/2 Medium swarm of Tiny beasts with AC 12, 22 hit points and resistance to bludgeoning, piercing and slashing damage. Its Bites deal 10 (4d4) piercing to a creature in its own space, dropping to 5 (2d4) once the swarm is at half its hit points or fewer. What sets it apart from the other insect swarms is a 5-foot burrow speed, so it can come up out of a dirt floor. It exists only in the 2014 rules: SRD 5.1 includes it under the Swarm of Insects, in the "Variant: Insect Swarms" section, and SRD 5.2.1 has no beetle version.
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.
Stat block from the SRD 5.1 (2014 rules) by Wizards of the Coast, licensed under CC-BY-4.0. Check an encounter with this monster in the encounter calculator.
The block is the SRD 5.1 Swarm of Insects plus one line from the "Variant: Insect Swarms" section that follows it: "A swarm of beetles gains a burrowing speed of 5 feet." Everything else is shared with the swarm of insects, so the general swarm rules apply in short form:
•Shared space. The swarm can enter a creature's space and a creature can enter the swarm's. Its Bites have a 0-foot reach and target one creature in its space, so it must move onto a character to attack.
•No healing. It can't regain hit points or gain temporary hit points. Every point of damage stays.
•Hard to pin down. It is immune to Charmed, Frightened, Grappled, Paralyzed, Petrified, Prone, Restrained and Stunned.
How a Swarm of Beetles Fights
The ambush comes from below. A 5-foot burrow speed is too slow for travel, but it is perfect for waiting. A swarm sitting just under a packed-earth floor, a midden or a sand pit can surface straight into a character's space and bite on the same turn. DM ruling, not rules text: the stat block says nothing about hiding while buried, so call for a Wisdom (Perception) check against a Stealth roll you make for the swarm (+1 Dex) or simply rule the party can't see it until it moves.
Damage math. Bites are +3 to hit. Against AC 14 that hits on an 11 or better, 50% of the time, for 5 expected damage a round. Against a fighter in chain mail and shield (AC 18), it hits on 15+, 30%, for about 3. Once the swarm is at 11 hit points or fewer, those numbers halve. Two healthy swarms on a level 1 wizard (AC 12, hits 60% of the time) average 12 damage a round, which is a dead wizard.
It is nearly blind. Its only sense is blindsight 10 feet and its passive Perception is 8. It doesn't chase what it can't sense. Run it as instinct: it goes for the nearest warm body and stays on it.
Slow on the surface. A 20-foot walk and climb speed means a character with 30 feet of movement can leave it behind. Use that: beetles are a hazard that punishes standing still, guarding a door or holding a choke point.
How Many Swarms of Beetles for Your Party?
A swarm is worth 100 XP. Using the 2024 XP budget and the 2014 guidelines our encounter calculator uses:
Party
Swarms
XP
2024 budget
2014 guidelines
4 level 1 characters
1
100
Low
Easy
4 level 1 characters
2
200
Low
Hard
4 level 1 characters
3
300
Moderate
Deadly
4 level 2 characters
4
400
Low
Deadly
4 level 3 characters
6
600
Low
Hard
The gap between the two systems comes from the 2014 group multiplier (×1.5 for two creatures, ×2 for three to six). For a party with no area damage, trust the 2014 number. One wizard with Burning Hands changes the whole fight.
How Players Beat a Swarm of Beetles
•Area damage.Burning Hands (3d6, average 10.5) or Thunderwave (2d8, average 9) hits every swarm in the area at full damage, but a swarm sitting in an ally's space means the ally is in the area too. Fireball (8d6, average 28) kills a swarm on a failed save.
•Persistent areas.Spirit Guardians punishes a creature that has to stay in your space to hurt you. Moonbeam works on a swarm holding a doorway or a dig spot, as long as no ally is in the cylinder.
•Weapons are half as good. A longsword hit for 7 deals 3 after resistance, so 22 hit points behave like about 44 against a party of weapon users.
•Skip control spells. Grapples, shoves to prone and fear effects all fail, and Hold Person can't target a Beast. The 2014 Sleep spell doesn't affect creatures immune to being charmed, so it does nothing here.
•Step away. The swarm moves 20 feet. Characters can retreat to a stone floor where it can't burrow up, and fight it in the open.
Swarm of Beetles Encounter Ideas
The dig site. Laborers at a barrow excavation refuse to work after dark. The spoil heaps beside the trench are loose earth, and three swarms of beetles live inside them. They come up into anyone who sits on a heap, which is where the laborers left the lantern and the dig foreman's ledger.
The carrion pit. A giant fire beetle colony glows under a ruined abbey, and the swarms are the small ones feeding on the same refuse. The light gives the party something to aim at. The swarms give them a reason not to stand still.
The sealed room. A wizard's specimen vault has a sand floor for "drying" exhibits. When the party lifts the bell jar in the center, two swarms surface around their feet. Pair them with a swarm of rats coming through the drain to make a two-front fight.
Frequently Asked Questions
What CR is a swarm of beetles in 5e?
A swarm of beetles is CR 1/2 and worth 100 XP. It has AC 12, 22 hit points and a +3 Bites attack that deals 10 (4d4) piercing damage, or 5 (2d4) at half hit points or fewer.
Is there a swarm of beetles in the 2024 rules?
No. The swarm of beetles appears in SRD 5.1 (2014) under the Swarm of Insects, in the "Variant: Insect Swarms" section. SRD 5.2.1 (2024) has a Swarm of Insects with poison Bites and no beetle variant.
Can a swarm of beetles burrow?
Yes. The beetle variant gains a burrowing speed of 5 feet on top of its 20-foot walk and climb speeds. That's slow, so it works best for ambushes from loose earth or sand.
Does a swarm of beetles resist weapon damage?
It resists bludgeoning, piercing and slashing damage, with no exception for magic weapons. Fire, cold, thunder, radiant and other damage types hit it for full damage.
Stat blocks: System Reference Document 5.1 (2014), Wizards of the Coast, CC-BY-4.0. Tactics, encounter math and ideas are Loreify's own.
This page includes material from the System Reference Document 5.1 and 5.2.1 by Wizards of the Coast LLC, available under the Creative Commons Attribution 4.0 International License. Loreify is not affiliated with Wizards of the Coast.