Hollow Fossil is a trinket in Fiend Folio, a mod for The Binding of Isaac.

+1.35 damage.

Crush Effect: Guarantees an Angel or Devil Deal on the current floor. Spawns a Black Heart instead of a Soul Heart.

The following special synergies and interactions for Hollow Fossil have been documented.

* Note that not all possible synergies and interactions are listed here.

• Check out the trinket description on the mod's external Wiki.
• Download Fiend Folio from the Steam Workshop.