Bone Mass
Huge • Undead • Neutral Evil
Armor Class 13
Hit Points 161 (17d12 + 51)
Speed 30 ft.
Initiative +0 (10)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 18 (+4) | 10 (+0) | 16 (+3) | 1 (-5) | 7 (-2) | 5 (-3) |
Damage Vulnerabilties bludgeoning
Damage Immunities piercing; necrotic, poison
Condition Immunities charmed, frightened, grappled, paralyzed, petrified, poisoned, prone, restrained, stunned
Senses blindsight 30 ft., passive Perception 8
Languages –
CR 9 (XP 5,000; PB +4)
Bloodied - Splinters. While bloodied, the bone mass creates an area of difficult terrain on the ground of its currently occupied space at the start of each of its turns. When a creature moves into or within that area, it takes 5 (2d4) piercing damage for every 5 feet it travels. The bone mass ignores the difficult terrain. As an action, a creature can clear a 5-foot square area, ending the effects in that particular space.
False Appearance. If the bone mass is motionless at the start of combat, it has advantage on its initiative roll. Moreover, if a creature hasn’t observed the bone mass move or act, that creature must succeed on a DC 15 Intelligence (Investigation) check to discern that the bone mass is animate. Additionally, the bone mass can spread its body over a 30-foot square area to look like a field of scattered bones and then accumulate in an unoccupied space in that area at the start of combat. When it does so, a creature has disadvantage on the Intelligence (Investigation) check.
Pile. The bone mass can occupy another creature's space and vice versa, and the swarm can move through any opening large enough for a Small creature. The bone mass heavily obscures the area outside its body for each creature inside its space, and vice versa.
Unusual Nature. The bone mass doesn't require air, food, drink, or sleep.
ACTIONS
Crush. Constitution Saving Throw: DC 16 (with disadvantage while grappled), each creature in the bone mass’s space. Failure: 25 (10d4) piercing damage and a target is knocked prone. Success: Half damage. Failure or Success: A target dies if it is reduced to 0 hit points by this attack. Its body is then absorbed into the bone mass, leaving only equipment behind, and the bone mass regains 20 hit points.
BONUS ACTIONS
Skeletal Grasp. Dexterity Saving Throw: DC 16, one creature in the bone mass’s space. Failure: The target is grappled (escape DC 16).
Bone Mass
Huge • Undead • Neutral Evil
Armor Class 12
Hit Points 123 (13d12 + 39)
Speed 30 ft.
Initiative +0 (10)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 16 (+3) | 10 (+0) | 16 (+3) | 1 (-5) | 7 (-2) | 5 (-3) |
Damage Vulnerabilties bludgeoning
Damage Immunities piercing; necrotic, poison
Condition Immunities charmed, frightened, grappled, paralyzed, petrified, poisoned, prone, restrained, stunned
Senses blindsight 30 ft., passive Perception 8
Languages –
CR 6 (XP 2,300; PB +3)
Bloodied - Splinters. While bloodied, the bone mass creates an area of difficult terrain on the ground of its currently occupied space at the start of each of its turns. When a creature moves into or within that area, it takes 2 (1d4) piercing damage for every 5 feet it travels. The bone mass ignores the difficult terrain. As an action, a creature can clear a 5-foot square area, ending the effects in that particular space.
False Appearance. If the bone mass is motionless at the start of combat, it has advantage on its initiative roll. Moreover, if a creature hasn’t observed the bone mass move or act, that creature must succeed on a DC 15 Intelligence (Investigation) check to discern that the bone mass is animate. Additionally, the bone mass can spread its body over a 30-foot square area to look like a field of scattered bones and then accumulate in an unoccupied space in that area at the start of combat. When it does so, a creature has disadvantage on the Intelligence (Investigation) check.
Pile. The bone mass can occupy another creature's space and vice versa, and the swarm can move through any opening large enough for a Small creature. The bone mass heavily obscures the area outside its body for each creature inside its space, and vice versa.
Unusual Nature. The bone mass doesn't require air, food, drink, or sleep.
ACTIONS
Crush. Constitution Saving Throw: DC 14 (with disadvantage while grappled), each creature in the bone mass’s space. Failure: 17 (7d4) piercing damage and a target is knocked prone. Success: Half damage. Failure or Success: A target dies if it is reduced to 0 hit points by this attack. Its body is then absorbed into the bone mass, leaving only equipment behind, and the bone mass regains 15 hit points.
BONUS ACTIONS
Skeletal Grasp. Dexterity Saving Throw: DC 16, one creature in the bone mass’s space. Failure: The target is grappled (escape DC 14).
Bone Mass
Huge • Undead • Neutral Evil
Armor Class 14
Hit Points 220 (21d12 + 84)
Speed 30 ft.
Initiative +0 (10)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 20 (+5) | 10 (+0) | 18 (+4) | 1 (-5) | 7 (-2) | 5 (-3) |
Damage Vulnerabilties bludgeoning
Damage Immunities piercing; necrotic, poison
Condition Immunities charmed, frightened, grappled, paralyzed, petrified, poisoned, prone, restrained, stunned
Senses blindsight 30 ft., passive Perception 8
Languages –
CR 12 (XP 8,400; PB +4)
Bloodied - Splinters. While bloodied, the bone mass creates an area of difficult terrain on the ground of its currently occupied space at the start of each of its turns. When a creature moves into or within that area, it takes 7 (3d4) piercing damage for every 5 feet it travels. The bone mass ignores the difficult terrain. As an action, a creature can clear a 5-foot square area, ending the effects in that particular space.
False Appearance. If the bone mass is motionless at the start of combat, it has advantage on its initiative roll. Moreover, if a creature hasn’t observed the bone mass move or act, that creature must succeed on a DC 15 Intelligence (Investigation) check to discern that the bone mass is animate. Additionally, the bone mass can spread its body over a 30-foot square area to look like a field of scattered bones and then accumulate in an unoccupied space in that area at the start of combat. When it does so, a creature has disadvantage on the Intelligence (Investigation) check.
Pile. The bone mass can occupy another creature's space and vice versa, and the swarm can move through any opening large enough for a Small creature. The bone mass heavily obscures the area outside its body for each creature inside its space, and vice versa.
Unusual Nature. The bone mass doesn't require air, food, drink, or sleep.
ACTIONS
Crush. Constitution Saving Throw: DC 17 (with disadvantage while grappled), each creature in the bone mass’s space. Failure: 35 (15d4) piercing damage and a target is knocked prone. Success: Half damage. Failure or Success: A target dies if it is reduced to 0 hit points by this attack. Its body is then absorbed into the bone mass, leaving only equipment behind, and the bone mass regains 30 hit points.
BONUS ACTIONS
Skeletal Grasp. Dexterity Saving Throw: DC 17, one creature in the bone mass’s space. Failure: The target is grappled (escape DC 17).
QUICK REFERENCE
Habitat
- Found in mass graves, ancient battlefields, and catacombs overflowing with unburied dead
- Common in necromancer lairs and sites of repeated ritual sacrifice
- Forms naturally in cursed lands where countless deaths have occurred over time
Behavior
- Lies motionless as a scattered pile of bones, mimicking a harmless debris field
- Shifts and grinds as it wanders aimlessly and mindlessly around
- Absorbs loose bones from the environment, slowly increasing its bulk
Information (Intelligence Check)
- DC 12 History: The creature can spread itself into a wide bone field and reassemble instantly
- DC 14 Investigation: Bones break easily when smashed with blunt weapons, but bone fragments make traversing difficult in the later stages of a fight
- DC 16 Medicine: Creatures killed by it are immediately absorbed into the mass and deskinned
Combat
- Usually lays in await as distributed field of bones and then ambushes enemies by re-forming directly around them
- Grapples with Skeletal Grasp to hold foes inside its body and guarantee disadvantage on their saves against Crush
- Moves over enemies and pulls grappled targets with it to maximum number of creatures inside it
- Keeps moving to new targets if available, especially at low hit points to create more areas with bone splinters
Loot Ideas
- Coin purses, pouches, and small valuables carried by the bone mass’s previous victims
- Weapons, armor pieces, or adventuring gear that remain (partially) intact after being trapped within the creature
- Bone fragments infused with negative energy useful for ritual components, divination tools, or necromantic focuses
USING MONSTER VARIANTS
Monster variants allow the GM to adjust encounters to better match the party’s strength, narrative needs, or world-building logic. A weaker variant may represent a juvenile, wounded, or lesser specimen, while a stronger variant can serve as a leader, champion, ancient creature, or apex predator.
Variants can be used to fine-tune difficulty without changing the core identity of the monster, making them ideal for scaling encounters, reinforcing hierarchy within a faction, or creating memorable boss-style enemies. You can even use the same stat block but different variants in the same encounter if you want.
Design Note. Each monster is primarily balanced around its normal version. Weaker and stronger variants are derived adjustments and may not always preserve every tactical nuance or “feel” of the original creature. GMs are encouraged to review variants carefully and adjust abilities or tactics as needed to best suit their table.