Oubliette



The Oubliette is a secret chamber in The Gungeon, accessed through a secret trapdoor in the Keep of the Lead Lord. The Oubliette takes the appearance of a sewer-like dungeon, containing trash bags, toxic waste pits, and harmless writhing Bullet Kin.

Accessing

 * The Keep of the Lead Lord always contains a room containing a Fireplace in the Keep of the Lead Lord, which can be extinguished with any non-oil Goop and then interacted with to reveal a room containing the hatch to the Oubliette.
 * One (or two) water barrels can almost always be found randomly in a separate room on the same floor.
 * This water barrel can rarely spawn inside of the Oubliette entrance room, which can make the sewers inaccessible.
 * After extinguishing the fireplace and activating it, the chance for a water barrel to spawn within the same room as the Fireplace increases dramatically for the save file.
 * The spawn chance for this water barrel appears to be independent from water barrel spawns outside of the fireplace room.
 * In some rare cases the second barrel might be in the hidden room, rendering it impossible to enter it when the first water barrel is destroyed.
 * After reaching the Oubliette once, the water barrel usually spawns in the fireplace room or a room adjacent to it.
 * The hidden room contains a hatch with two locks. Unlocking both locks (which takes 2 keys) opens the trapdoor, and entering the trapdoor leads to the Oubliette.
 * These locks work identically to wall locks and can be opened with Trusty Lockpicks or a Drill.
 * Entering the Oubliette for the first time unlocks Trashcannon and the Grate Hall achievement.

Boss
Like all bosses in secret floors, there is no Master Round for beating Blobulord flawlessly.

Trivia

 * An oubliette is a secret dungeon with access only through a trapdoor in its ceiling, fitting with the chamber's method of access.
 * It is possible to enter the trapdoor while flying. The game will freeze for a brief moment and skip straight to the loading screen of the Oubliette without a falling animation.
 * Several of the decorations found here are unique to the Oubliette.
 * One decoration unique to the Oubliette is a barrel with the tip of a Bulletkin protruding from it.
 * This may be a reference to a similar prop seen in Blighttown, an infamous, similarly themed level featured in Dark Souls.
 * This is also a play on the idea of a bullet in the barrel of a gun.
 * Oubliette is pronounced "oo-blee-et" /u.bliˈɛt/
 * The Lost Adventurer talks about a switch behind a fireplace when interacted with at the Breach.
 * You can access the Oubliette trapdoor room without dousing the fireplace by using Teleporter Prototype.