Fossils: all 9 fossil items

Primal Dread adds nine fossil items. Each fossil can be bought once, and most have a bonus that grows for every fossil you have equipped. Equipping five fossils in one run completes the Bone Collector challenge, which unlocks the Caveman.

All nine fossils

The effect column shows the launch values from the game files. The 12 November patch raised bonuses and lowered maluses; the change column quotes the patch notes.

Fossil	Tier and price	Launch effect	12 November change
Tooth	Common, 25	Counts as a fossil; −2 Max HP	−1 Max HP (was −2)
Right Arm	Uncommon, 30	+1 Max HP; −2% Dodge; +1 Max HP per fossil	+3 Max HP (was +1), +2 Max HP per fossil (was +1)
Left Leg	Uncommon, 30	+1% Speed; −3% Crit Chance; +1% Speed per fossil	+3% Speed (was +1%), +2% Speed per fossil (was +1%)
Right Leg	Uncommon, 30	+5 Range; −4% Attack Speed; +5 Range per fossil	+15 Range (was +5)
Jaw	Uncommon, 35	+1% Life Steal; −3 HP Regeneration; +1% Life Steal per fossil	+3 Life Steal (was +1), +2 per fossil (was +1), −2 HP Regeneration (was −3)
Spine	Uncommon, 35	+2 HP Regeneration; −5% Damage; +1 HP Regeneration per fossil	+3 HP Regeneration (was +2), +2 per fossil (was +1)
Tail	Uncommon, 45	+5 Harvesting; −3 Max HP; +3 Harvesting per fossil	Not listed in the patch notes
Left Arm	Rare, 60	+1 Armor; −3% Speed; +1 Armor per fossil	+3 Armor (was +1)
Skull	Rare, 70	+10% Damage; −5% Dodge; +3% Damage per fossil	+5% Damage per fossil (was +3%), −3 Dodge (was −5)

Prices are base prices; the shop raises them as waves pass. For Right Leg and Left Arm the notes do not say whether the change applies to the flat bonus, the per-fossil bonus, or both.

Buying fossils for the Caveman unlock

• Tooth is the cheapest and has the smallest penalty, so it is the easiest fifth fossil.
• Skull and Left Arm are Rare and appear less often in early shops. Lock a fossil when it shows up if you cannot afford it yet.
• Fossils are tagged by the stat they give (Skull is a Damage item, Left Arm an Armor item), so a character whose shop favours one stat sees its fossil more often.

Fossils with Mutant Evolution

A mutation can remove a fossil’s malus or copy its effect onto the Tumor. Players have reported fossil effects among the copied lines. See how mutation works.