Boss Shrine is an unlockable machine in TBoI: Retuned, a mod for The Binding of Isaac.

Can only spawn on II stages or XL floors of chapters up to Depths.

Upon interacting with it, Isaac is teleported to a special Boss Room layout.

These Boss Rooms contain 1-2 bosses from the next chapter and give the following rewards:
• 1 random food item.
• 2 Boss Room items to choose between.

Defeat Mega Satan as Cadence.

• Download TBoI: Retuned from the Steam Workshop.