Binding of Isaac: Rebirth Wiki
Binding of Isaac: Rebirth Wiki
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(Added fortune cookie as a recommended item)
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*{{I|Birthright}} will double the effectiveness of HP upgrades, meaning ??? gains twice as many soul hearts as normal.
*{{I|Birthright}} will double the effectiveness of HP upgrades, meaning ??? gains twice as many soul hearts as normal.
**This can be exploited with {{I|Converter}} to generate unlimited HP.
**This can be exploited with {{I|Converter}} to generate unlimited HP.
*{{I|Fortune Cookie}} can give a soul heart upon use.
=== Negative ===
=== Negative ===

Revision as of 10:06, 8 May 2021

Disambig.png This article is about the playable character. For other uses, see ??? (Disambiguation).

???, also known as the Blue Baby, is a character unlocked by defeating Mom's Heart ten times. He starts with three Soul Hearts, and his health meter is unique in that he cannot gain red heart containers. If an item would grant him a red heart container (including an empty one), it adds a Soul Heart instead.


  • Sleeping on a bed will give ??? three Soul Hearts.
  • Enemies who deal full hearts of damage can be very dangerous in the early floors of the game.
  • 15►The Poop The Poop - While not the most useful item, it can allow ??? to cross small gaps by bombing the Poop from the opposite side, much like one would for Rocks. Furthermore, in rooms with non-flying enemies that chase the player (except Spiders), the poop can be used in a corner of the room making ??? untouchable, allowing the player to kill them without taking damage (if the player moves away from the pile of Poop generated, this will no longer work).
  • Bone Hearts grant an empty Bone Heart upon pickup, but they cannot be refilled using Red Hearts.

Item Interactions

  • Added in Repentance15►Birthright Birthright: Soul hearts gained from health ups will be doubled. Health down pills will remove 2 soul hearts instead of 1, however.


  • Removed in Repentance15►Abaddon Abaddon costs three Soul Hearts and grants six Black Hearts, damage up, fear shot, and no negative effects to ???. Abaddon can be bought safely regardless of current health, because its price can be deducted from the acquired Black Hearts retroactively.
  • Added in Repentance15►Abaddon Abaddon will give 2 black hearts on pickup, granting its effects essentially for one heart.
  • 15►Ankh Ankh is effectively a 15►1up! 1up! for ???.
  • Added in Afterbirth / Removed in Repentance15►Athame Athame can be used to produce black hearts upon taking damage.
  • Balls of Steel pills or V - The Hierophant V - The Hierophant grant two soul hearts, both of which are more useful than normal HP up items.
  • The Rune of Dagaz Rune of Dagaz grants one soul heart as well as lifting any curses.
  • Removed in Afterbirth The XI - Strength XI - Strength card gives ??? a permanent soul heart.
  • 15►Book of Revelations Book of Revelations Spawns soul hearts.
  • 15►Ceremonial Robes Ceremonial Robes costs three Soul Hearts and grants three Black Hearts and damage up. Removed in Repentance Like 15►Abaddon Abaddon, this item is always safe to take.
  • Added in Afterbirth15►Crown of Light Crown of Light will always activate.
  • 15►Mitre Mitre and Daemon's Tail Daemon's Tail replace useless Red Hearts with Soul and Black Hearts respectively.
  • 15►Dark Bum Dark Bum converts useless Red Hearts into Black Hearts and Spiders.
    • Added in Repentance Dark Bum can now also drop pills, cards, and runes, which can include The Hierophant, Balls of Steel, or Dagaz.
  • 15►Dead Cat Dead Cat will set Soul Hearts to 1, but can be used to gain devil deals by sacrificing the extra lives.
  • Added in Afterbirth †Dim Bulb Dim Bulb is able to be activated every room due to the single charge on 15►The Poop The Poop, providing a consistent stat boost.
  • 15►Gimpy Gimpy has a chance to spawn Soul Hearts when hit.
  • Added in Afterbirth †15►Hallowed Ground Hallowed Ground turns all 15►The Poop The Poop uses into holy poops.
  • 15►Lazarus' Rags Lazarus' Rags causes ??? to be resurrected as Lazarus Risen when he dies, allowing the gathering of heart containers. Once this happens, however, you are no longer playing as ???, and therefore cannot get any of his achievements/unlocks. The same effect happens with the use of 15►Judas' Shadow Judas' Shadow.
  • Added in Afterbirth / Removed in Repentance15►Maw of the Void Maw of the Void can produce Black Hearts.
  • 15►Midas' Touch Midas' Touch makes 15►The Poop The Poop create Golden Poop.
  • Monkey Paw Monkey Paw will drop 3 Black Hearts, but must take damage for each one to spawn.
  • Petrified Poop Petrified Poop is useful early on to get more pickups from 15►The Poop The Poop every room.
  • 15►The Polaroid The Polaroid and 15►The Negative The Negative always activate when taking damage.
  • 15►The Relic The Relic, which is generally useful, is especially useful to ??? as it spawns Soul Hearts.
  • 15►Satanic Bible Satanic Bible generates Black Hearts.
    • Added in Repentance Using Satanic Bible now also causes boss items to turn into devil deals that cost hearts, so it may be best to hold off on using it until after the boss fight if ??? is low on health.
  • Added in Afterbirth15►Serpent's Kiss Serpent's Kiss can produce Black Hearts by poisoning enemies.
    • Added in Repentance Serpent's Kiss now only produces Black Hearts from contact damage poison, making it slightly less useful for ???.
  • 15►Squeezy Squeezy and Added in Afterbirth15►Mr. Dolly Mr. Dolly increase ???'s tears and can grant Soul Hearts.
  • 15►Whore of Babylon Whore of Babylon is always active.
  • Added in Repentance15►Birthright Birthright will double the effectiveness of HP upgrades, meaning ??? gains twice as many soul hearts as normal.
    • This can be exploited with 15►Converter Converter to generate unlimited HP.
  • Added in Repentance15►Fortune Cookie Fortune Cookie can give a soul heart upon use.


  • Items that directly add Red Hearts to the health bar, such as 15►Yum Heart Yum Heart or full health pills, are useless.
  • Blood Donation Machines and Devil Beggars are riskier, as they deplete health that is harder to replenish.
  • If ??? has only one heart, 15►Experimental Treatment Experimental Treatment has a chance to be lethal.
  • Cursed Skull Cursed Skull will automatically teleport ??? out of the room upon taking any damage, as he doesn't have any Red Hearts.
  • Added in Afterbirth / Removed in Repentance15►Glass Cannon Glass Cannon will bring ??? down to half a Soul Heart, and not give back any health upon leaving a room due to ???'s lack of Red Hearts. This item essentially takes away most of the player's health in exchange for a single high damage tear.
    • Added in Repentance This effect no longer applies in Repentance, making it a more viable choice. Even so, caution should be used, as taking damage will cause all subsequent damage taken in the room to be two full soul hearts, making this especially risky for ???.
  • 15►Guppy's Paw Guppy's Paw, since requiring Red Hearts to convert, would be a useless item to hold (but should still be picked up and swapped back to get credit towards the Guppy transformation). Guppy's Paw may still be used to activate Broken Remote Broken Remote.
  • Judas' Tongue Judas' Tongue doesn't lower the price of Soul Heart Devil deals.
  • 15►Little C.H.A.D. Little C.H.A.D. is useless unless paired with 15►Dark Bum Dark Bum, where it becomes very useful.

Unlockable Achievements


  •  ??? appears in the original Binding of Isaac.
    •  ???'s unlock requirements in Rebirth are the same in the original Binding of Isaac.
  • The name "Blue Baby" had not appeared in the game itself until the Afterbirth expansion, with a co-op baby named as such.
  •  ???'s common nickname, Blue Baby, is a reference to blue baby syndrome, in which a baby's skin complexion appears blue from a lack of oxygen in its blood due to a congenital heart defect.
  • Many of Edmund's older flash games from Newgrounds feature ??? and 15►Brother Bobby Brother Bobby. ??? was Edmund's mascot from 1996-2002.
  • In several cutscenes, Isaac is depicted suffocating inside a chest. ??? is first seen inside an identical chest, and is the follow up boss after Isaac. Blue skin tone is typically used to show suffocation, and X eyes imply that the character is either knocked out or deceased.
    • After death, the bowels of the deceased will loosen, causing them to defecate themselves. This is most likely the reason ??? starts with 15►The Poop The Poop.
  • Unlike many of the other characters, ??? does not appear in the Bible or any religious scripture. He is the first character with this distinction, and the only one to appear in the original Binding of Isaac - the second being The Lost in Rebirth.
  • The 15►Ankh Ankh will resurrect any character as ???, even before he is unlocked.
  • Although "Blue Baby" is considered an unofficial nickname for ???, the character is referred to by this name in some of the game's code. One example of this is the image file for the character, named character_006_bluebaby.
  •  ???'s look originally came from Dead Baby Dressup, one of Edmund McMillen's first Flash games.
  •  ???'s starting health is listed as "-1" on the character selection screen.



Isaac CharNav New.png Maggy CharNav New.png Cain CharNav New.png Judas CharNav New.png BB CharNav New.png Eve CharNav New.png Samson CharNav New.png Azazel CharNav New.png Lazarus CharNav New.png Eden CharNav New.png Lost CharNav New.png


Tainted Isaac CharNav New.png Tainted Maggy CharNav New.png Tainted Cain CharNav New.png Tainted Judas CharNav New.png Tainted BB CharNav New.png Tainted Eve CharNav New.png Tainted Samson CharNav New.png Tainted Azazel CharNav New.png Tainted Lazarus CharNav New.png Tainted Eden CharNav New.png Tainted Lost CharNav New.png Tainted Lilith CharNav New.png Tainted Keeper CharNav New.png Tainted Apollyon CharNav New.png Tainted Forgotten CharNav New.png Tainted Bethany CharNav New.png Tainted Jacob CharNav New.png

The Binding of Isaac: Rebirth The Binding of Isaac: Rebirth The Binding of Isaac: Rebirth
Achievements Achievements Attributes Attributes Bosses Bosses TarotCard.png Cards and Runes Challenges Challenges Chapters Chapters
Characters Characters MainPageBabies.png Co-op Items Items Item pools Item pools Monsters Monsters Objects Objects
Pickups Pickups Pills Pills Rooms Rooms Seeds Seeds Transformations Transformations Trinkets Trinkets