Valheim's third boss is a creature directly from the Swamp, made of bones and gelatinous goo. It's one of the most intimidating bosses in all of Valheim. With that, here's everything you need to know about the Bonemass boss in Valheim, including how to summon it, and some fight tips and tricks that may help you conquer this mighty foe.

How to Summon Bonemass in Valheim

To summon Bonemass, players will need to acquire some materials, do some exploring, and find his spot in the Swamp biome. In particular, to find Bonemass's location, players must descend into the Sunken Crypts, the skeleton dungeons, for a Vegvisir runestone. Interact with it to reveal the location of the boss’s summoning altar on the map. It’s also important to mention that Bonemass’s summoning altar is a giant, green, glowing skull. Once you've got the summoning altar's location, you'll bring 10x Withered Bone to the altar. If you don’t have enough, check the Sunken Crypts and Muddy Scrap Piles in the Swamp biome to collect ten of this material. Then, “feed” the Withered Bones to the giant skull to summon the boss.

How to Defeat Bonemass (Fight Tips & Tricks)

The Elder may be a big step up in difficulty from Eikthyr, but Bonemass is another leap entirely. Bonemass is a lethal threat throughout the entirety of the fight, much like the other creatures of the Swamp biome. It’s also a massive boss, and will challenge players to navigate tricky terrain in the Swamp to escape his pursuit. To prepare for the boss fight, you'll need plenty of Poison resistance, as all of Bonemass' attacks deal Poison damage. You should also rely on blunt weapons, as they perform extremely well against Bonemass and his Slimes. Once you have the right tools and supplies, it's time to learn what moves to look out for on Bonemass. Bonemass has three different attacks:

• Charging up a green poisonous cloud that deals damage in a massive area.
• Swiping at players when in melee range.
• Summoning Skeletons and Slimes by throwing out a ball of goo.

The most important time to attack Bonemass is during his summoning animation, where he will lean back, and pull out a ball of goo from his body, and then throw it out. Players can get some quick damage in around this time window, on top of utilizing ranged attacks and catching Bonemass while moving. Once you get the hang of these abilities and their animations, killing Bonemass is all about keeping high enough health to survive poisonous area of effect attacks and spawned enemies while still delivering damage throughout. Positioning is key, and bringing friends certainly won't hurt your chances. Below are additional tips to consider to help you bring down this grotesque creature:

• Wear Iron Armor. At this point, this armor set should provide the necessary defense stats to help you survive Bonemass’s powerful melee attacks. Equipping a sturdy shield is also ideal for blocking or parrying his swings.
• Stock up on mead and food. The Poison Resistance Mead, in particular, is a must-have for this fight. Without it, Bonemass’s poison attacks can quickly overwhelm underprepared players.
• Know when to retreat. There’s no shame in running away from Bonemass when the going gets tough. Thankfully, this boss is quite slow, making escape fairly easy.

Bonemass Loot & Rewards

Defeating Bonemass rewards players with a few yet meaningful progression items in Valheim. The first item of note is a Wishbone, which emits visual and audio signals that lead players to buried treasures in Muddy Scrap Piles at the Swamp biome, the ground underneath the Mountain biome, and other locations. Another notable reward from winning this fight is the Bonemass Trophy. Hang it on your base, and you and your friends in the Valheim server can take advantage of the Bonemass Forsaken Power. With it active, adventurers can take advantage of the following buffs for 300 seconds:

• Slightly increases resistance to Blunt, Slash, and Pierce damage
• -100% to Block Stamina Usage
• +5 to Block Stamina Return

Additionally, besting the Bonemass in battle lets Skeletons to spawn in other biomes, namely the Meadows, Plains, Mountain, and the Black Forest. However, these undead creatures of the night will only be at 0 stars if they spawn outside the Swamp.