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

Added in Afterbirth †

Delirious is an unlockable active item added in The Binding of Isaac: Afterbirth †.


  • Upon use, spawns Delirium in a form of a friendly boss for the current room.
  • Changes the appearance of the current room so it looks like a different chapter.


  • If multiple bosses are spawned in one room with Car Battery Car Battery, The Battery The Battery, or batteries, the bosses can try to kill each other.
  • Sometimes bosses don't spawn because of grid entities getting in the way. When this happens the upper door appears to have friendly particles.
  • Removed in Repentance Unlike Mega Blast Mega Blast, this item can be charged with a single Lil' Battery.
  • It is possible for Hush to spawn, despite Delirium not transforming into Hush during its boss battle.
  • If a boss summons monsters, the monsters will be charmed and will follow Isaac out of the room.
  • Delirious has a 60% decreased item pool weight, making it less likely to appear than other collectibles.


  • Added in RepentanceBook of Virtues Book of Virtues: Generates a white wisp that resembles one random boss from this list:
    • Monstro: Fires an inaccurate spray of 6-10 tears at a time, similarly to Monstro's Lung Monstro's Lung but without the charge time.
    • The Duke of Flies: Each wisp will create and can have up to 3 Blue Flies out at a time, similar to Rotten Baby Rotten Baby.
    • Loki: The direction the tears are fired alternates between the cardinal and ordinal directions, similar to Loki's Horns Loki's Horns.
    • The Haunt: Fires Brimstone Brimstone lasers. The laser does not need to be charged to be fired, and can tick up to 8 times for a total of 8 damage.

In-game Footage[]


  • This item was most likely intended to be the "ultimate item" of Afterbirth †, similar to Mega Blast Mega Blast of the Afterbirth DLC.


PS4 T71G R34M (Starting item as Eden)

PS4 LBQ4 V4NT (Starting item as Eden; player will also start with Tech X)

PC YBCK TTZB (Starting item as Eden)


Bug Bug! If Delirious is used during the Delirium fight and the charmed boss is killed, it will act as if Delirium was killed, but no chest will spawn.
Bug Bug! If a Pink Champion Polycephalus is spawned by the item, one will have the Delirium skin and the other will have the normal Polycephalus skin.
Bug Bug! If Lokii is spawned by the item, one will have the Delirium skin and the other will have the normal Lokii skin.
Bug Bug! If a Pink Champion The Cage is spawned by the item, one will have the Delirium skin and the other will have the normal The Cage skin.
Bug Bug! Using Delirious multiple times rapidly in the same room can crash the game.
Bug Bug! Using Delirious during the Beasts Harbinger phase may cause the phase to never end.
Bug Bug! Using Delirious in Boss Rush or Boss Challenge Room can close the exit even if it was finished beforehand, likely softlocking the player.
Bug Bug! Using Delirious can sometimes spawn a boss without its Delirium skin.
Bug Bug! If Delirious is used against Loki in a room layout where a Poky is present, the Poky will not deactivate until the boss and any enemies it spawns die (which may take an extremely long time). If the player has no card, pill, or rune to teleport them out of the room, this is effectively a softlock.
Bug Bug! Added in Repentance PC If used during the fight with The Beast, it will break visuals and make the fight harder to play.