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Bone Swarm

Large · Undead · CR 10 · Chaotic Evil

Source. Tome of Beasts 1 (2023 Edition)

17 (natural armor)

198 (36d10)

Ability Scores

Core attributes and their modifiers.

STR

DEX

CON

INT

-1

WIS

CHA

Overview

Category Monsters

Size Large

Type Undead

Alignment Chaotic Evil

XP 5900

Initiative Bonus +4

Movement

Walk 60 ft (18.3 m)

Fly 20 ft (6.1 m)

Swim 30 ft (9.1 m)

Climb 30 ft (9.1 m)

Crawl 30 ft (9.1 m)

Senses

Darkvision 60 ft (18.3 m)

Passive Perception 16

Saving Throws

Dexterity +8 Wisdom +6 Charisma +9

Skills

Acrobatics +8 Perception +6 Stealth +8

Languages

Common, Void Speech

Resistances & Immunities

Damage Immunities

poison

Damage Resistances

piercing and slashing from nonmagical attacks

Damage Vulnerabilities

bludgeoning

Condition Immunities

charmed, exhaustion, frightened, grappled, paralyzed, petrified, poisoned, prone, restrained, stunned

Traits

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 human skull. The swarm can’t regain hp or gain temporary hp.

Undead Nature

The bone swarm doesn’t require air, food, drink, or sleep.

Actions

Death's Embrace

Recharge 5–6

Melee Weapon Attack: +10 to hit, reach 0 ft., one creature in the swarm's space. Hit: The target is grappled (escape DC 16) if it is a Large or smaller creature. Until this grapple ends, the creature is restrained and any attack against the bone swarm has a 50 percent chance of hitting the grappled creature instead. The bone swarm can have only one creature grappled at a time. The grappled creature has advantage on ability checks made to escape the grapple when the bone swarm has half of its hp or fewer.

Multiattack

The bone swarm makes two Swirling Bones attacks. It can replace one Swirling Bones attack with one Death's Embrace attack, if available.

Swirling Bones

+10 to hit. Hit: 8d8 slashing damage.

Melee Weapon Attack: +10 to hit, reach 0 ft., one creature in the swarm's space. Hit: 36 (8d8) bludgeoning, piercing, or slashing damage (the bone swarm's choice), or 18 (4d8) bludgeoning, piercing, or slashing damage (the bone swarm's choice) if the swarm has half of its hp or fewer.

About Bone Swarm

Bone Swarm is a large undead with a Challenge Rating of 10. It has a chaotic evil alignment.

In combat, this creature maintains an Armor Class of 17 and possesses 198 hit points (derived from 36d10).

Bone Swarm has communication capabilities including Common, Void Speech. This allows it to interact verbally with various creatures and characters.

GM Tips: Using Bone Swarm

1 tips available

When using Bone Swarm in your D&D 5e campaign, consider these tactical approaches:

Flight Control Strategy: Target flying creatures with spells like 'Hold Person', 'Web', or 'Grease' to ground them. Without flight restriction, they can escape melee range easily. Consider area denial spells below their flight altitude to force them into disadvantageous positions.

Player Guide: Facing Bone Swarm

1 strategies available

When your party encounters this creature, keep these strategies in mind:

Counter Flight Advantage: This creature can fly! Use ranged attacks, reach weapons, or spells like 'Thunderwave' to push it away. Consider 'Gust of Wind' or 'Earthbind' to ground it. Melee characters need fly speed or flight magic to engage.

Encounter Building Calculator

Standard Party Encounter (4-5 characters):

This creature is a medium encounter for a party of 4 characters of level 10.

Solo Encounter:

A single character of level 13 (up to level 20) can face this creature in a medium to hard encounter.

Experience Point Thresholds:

Medium: 11,000 XP
Hard: 16,500 XP
Deadly: 22,000 XP

Based on D&D 5e Dungeon Master's Guide encounter building guidelines. CR roughly equals party level for medium encounters.

Frequently Asked Questions

What is the challenge rating of Bone Swarm?: Bone Swarm has a Challenge Rating of 10, making it appropriate for parties of level 10.0.
What type of creature is Bone Swarm?: Bone Swarm is a Large Undead, which affects how certain spells and abilities interact with it.
What languages does Bone Swarm speak?: Bone Swarm can communicate in Common, Void Speech.