Binding of Isaac: Rebirth Wiki

(in Afterbirth † and Repentance)

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

Effect[ | ]

  • Upon use, spawns Boss Delirium ingameDelirium 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.

Notes[ | ]

  • Sometimes bosses don't spawn because of grid entities getting in the way. When this happens, the upper door appears to have friendly particles.
  • (except in Repentance) Unlike Collectible Mega Blast iconMega Blast, this item can be charged with a single Lil' BatteryLil' Battery.
  • (in Repentance) Lil' BatteryLil' Battery gives 6 charges.
  • It is possible for Boss Hush ingameHush to spawn, despite Delirium not transforming into Hush during its boss battle.
  • If a boss summons monsters, the monsters will be friendly and will follow Isaac out of the room. A large army of friendly enemies can be created by waiting in the room.
  • Delirious has a 60% decreased item pool weight, making it less likely to appear than other collectibles.
  • Certain large bosses with high health like Boss Hush ingameHush can block projectiles while Isaac stays within their hitbox, with enemies often dying when they touch the boss. Very useful for bullet heavy bosses.
  • Using Delirious in the Delirium fight is ill-advised, as the player may confuse which Delirium is the right one to attack, often causing more chaos in an already chaotic battle.
  • Some bosses leave fires on the ground, such as the orange champion Boss Little Horn ingameLittle Horn, which can still hurt Isaac.

Synergies[ | ]

  • (in Repentance)Collectible Book of Virtues iconBook of Virtues: Generates a white wisp that resembles one random boss from this list:
    • Boss Monstro ingameMonstro: Fires an inaccurate spray of 6-10 tears, similar to Collectible Lil Monstro iconLil Monstro but without the charge time.
    • Boss The Duke of Flies ingameThe Duke of Flies: Creates Blue Flies instead of firing tears. Each wisp can have a maximum of 3 flies at a time.
    • Boss Loki ingameLoki: Fires four tears that alternate between cardinal and ordinal directions.
    • Boss The Haunt ingameThe Haunt: Fires Collectible Brimstone iconBrimstone 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.

Interactions[ | ]

  • (in Repentance)Collectible Blood Puppy iconBlood Puppy: Either angry version of Blood Puppy will target friendly bosses as well and can drag them along with it when it charges them. Blood Puppy cannot damage friendly bosses; however, friendly bosses can damage Blood Puppy despite not targeting it outright.
  • Collectible Broken Modem iconBroken Modem: Broken Modem also affects friendly bosses and projectiles created by them.
  • (in Repentance)Collectible Eraser iconEraser: The thrown Eraser can’t hit friendly bosses; however, if it erases their hostile variant, they too are erased. If Delirious attempts to spawn an erased boss, it will fail to do so, wasting a use.
  • (in Repentance) Collectible Ghost Bombs iconGhost Bombs / Collectible Hungry Soul iconHungry Soul / Collectible Purgatory iconPurgatory / Collectible Vade Retro iconVade Retro: Explosions from ghosts can harm friendly bosses.
  • TickTick: Friendly bosses start with less health if they have over 60HP.

In-game Footage[ | ]

Trivia[ | ]

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

Bugs[ | ]

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 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! Using Delirious during Mega Satan or Beast fight can lead to a softlock.
Bug Bug! If a Mega Fatty is spawned by the item during The Beast fight, when the Mega Fatty inhales, it will move the sprites of the bosses in the background.
Bug Bug! If Delirious summons Rag Mega in an uncleared room, the Purple Balls will prevent the room from clearing, effectively causing a lengthy softlock - The friendly Rag Mega does steadily lose health on his own, but this takes a fair while.
Bug Bug! If Delirious spawns Chub, C.H.A.D., or Carrion Queen, only their head will appear.