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Bonemass is the third boss. He appears as a gigantic humanoid mass comprised of toxic ooze, mud and skeletal remains, likely absorbed from nearby tombs situated close to his altar.



Bonemass' Forsaken Altar.

Bonemass' Forsaken altar is located in Swamps. His location can be found when visiting Sunken Crypts and sometimes ruined structures, where a Vegvisir will reveal his nearest summoning location on the map.

He is summoned by placing 10 Withered bone Withered bones in his Forsaken altar in Swamps. Like all bosses, Bonemass can be summoned as many times as desired, provided the required materials are met.  

Attacks and abilities[]

For strategies for defeating Bonemass, see Boss strategies § Bonemass.

Bonemass has an environment aura that forces raining, which means pulling him from the area cannot be used to remove Wet.


A close-range swipe at a player dealing up to 80 Blunt and 30 Poison damage to players, and 1000 Chop and 1000 Pickaxe damage to any trees or rocks hit.

Area of effect[]

Bonemass will charge up with a thick green cloud before releasing a wave of poisonous ooze, poisoning everything in a wide range around him (100 Poison damage). This is signaled when he leans backwards. The poison cloud persists for several seconds and will continuously refresh the poison duration on any player that stays inside.


At intervals, Bonemass will reach into his armpit to throw out a glob of goop. This is never directed at a player, and will spawn up to four random monsters (skeletons and/or blobs) where it lands. No more of a creature type will be spawned once eight of that type are already present.


Defeating Bonemass provides the player with a Wishbone, which allows the player to easily locate Silver veins beneath the surface of Mountain biomes (as well as buried muddy scrap piles in Swamp biomes, and other miscellaneous buried treasures in certain locations).


Item 0 Star
Bonemass trophy Bonemass trophy 1
Wishbone Wishbone 1 per player

Forsaken power[]

Mounting Bonemass' trophy upon his respective stone will allow the player to claim his Forsaken Power. This ability will grant the player and nearby allies 50% resistance to Blunt, Slash and Pierce damage types for five minutes.

See Bonemass' power for more details.


Defeating Bonemass affects the following events for that world:

  • Disables: Draugr and Skeleton "A foul smell from the swamp..."
  • Enables: Blobs and Oozers "A foul smell from the swamp..."
  • Enables: "A skeleton surprise!"
  • Enables: "A cold wind blows from the mountains." (if Moder has not been defeated)
  • Enables: "There's a smell of sulfur in the air." (if a Surtling has died)
  • Enables: "You are being hunted."
  • Enables: "You stirred the cauldron." (if a Bat has died)

Note: Two of these events unlock flying enemies that will be uninhibited by base walls and will attack tame animals. For example, bats will quickly wipe out any outdoor tame boars (if the player has them), most likely before the player can swat them all. Therefore, in order to protect any rare animals (such as a 2-star Boar), it is advisable to build a secure indoor barn area before undertaking Bonemass.

Creature spawning[]

Defeating Bonemass unlocks skeletons to spawn at night in the Meadows, Black Forest, Swamp (additional), Mountain and Plains. They can only have 0 stars.



  • Bonemass has undergone a model change since Valheim's release.
  • In the in-game trophies menu, there is another description of Bonemass, "A mess of black soil and old bone, thankfully quiet now."