The Forgotten Map is a unique, powerskill which can only be used once per run that reveals the full layout of the current biome.
Using the Forgotten Map reveals the full layout of a biome, with its exits and boss cell doors, as well as any scrolls, starred enemies, and loot hidden within secret areas. It is consumed upon use and disappears from the player's inventory.
Starred enemies may carry scrolls, legendary items or corrupted artifacts.
When the Specialist's Showroom upgrade is unlocked, the Forgotten Map can be found in a cell next to the Hunter's Grenade. The player can unlock it for 4000 Gold or destroy the gate for a 50-kill Curse.
When used, the game will say "You have been initiated into the secrets of the Architects".
The Forgotten Map, Blueprint Extractor and Hunter's Grenade are the only single-use skills in the entire game.