Binding of Isaac: Rebirth Wiki
Binding of Isaac: Rebirth Wiki

Added in Repentance

Hornfel is a boss added in The Binding of Isaac: Repentance that can appear in Mines Mines.


Phase 1[]

He appears with his own specially designed boss room, where the walls are covered in boss doors, with minecart tracks connecting them. Hornfel rides a minecart along these tracks and performs the following attacks upon entering the room:

  • Occasionally, when Hornfel enters the room through a door, he is accompanied by 2 Fly Bombs.
  • Throws 1-2 Bombs at Isaac. Additionally, each bomb has a small chance of having the 15►Hot Bombs Hot Bombs or 15►Sad Bombs Sad Bombs effect.
  • Throws 3 15►Brimstone Bombs Brimstone Bombs that resemble mines. Each has a delay and detonates after a few moments.
  • Accelerates along one set of tracks, while frequently throwing out bombs for the duration. Slows down after multiple cycles, before getting sick and vomiting a fireball that release fire trails in the cardinal directions upon landing.
  • Sends out 1-2 decoy dummies with 4 HP on other tracks that burst into 6 Troll Bombs if killed or walked into.
  • Other minecarts occasionally appear on other tracks independent of Hornfel, carrying fire, TNT, or a variety of other enemies:

Hornfel and his decoys deal a whole heart of contact damage.

Phase 2[]

Once Hornfel has taken enough damage, he falls out of his minecart and attempts to escape from the room via one of the doors surrounding the arena. He makes no attempt to attack Isaac but he can still deal contact damage (Though this is reduced to half a heart from a whole heart).

  • Other minecarts carrying other monsters and objects can still appear as usual during this phase.
  • If Hornfel escapes successfully, the fight ends as normal.
  • If Hornfel is defeated, he drops either 3 Bomb pickups, 15►Boom! Boom!, 15►Brimstone Bombs Brimstone Bombs or 15►Remote Detonator Remote Detonator and unlocks 15►Brimstone Bombs Brimstone Bombs, if not already unlocked.


Unlockable Achievements[]


  • Hornfels is the group name for a set of contact metamorphic rocks. They are known to be very hard and durable.
  • The Horny Boys are a stitched amalgamation of Hornfel and Loki.


Bug Bug! If Hornfel is killed off screen the game crashes.

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