Prison key

Prison keys are special keys found by completing secrets or by finding prison key pickups throughout runs. Unlike other pickups, prison keys can be spawned when defeating an enemy, instead of after a room has been cleared. Every enemy has its own prison key, and a very low chance of dropping it upon defeat. Prison keys serve no benefit during a game and cannot be recycled, but can be redeemed via The Imprisoned to unlock relics in exchange for soul coins, requiring more soul coins for a higher rarity relic. When a relic is unlocked via The Imprisoned, the player is given this relic during the next run they play, although no more than two can be brought at once.

A prison key pickup