??? (Boss)

This article is about the boss at the end of The Chest. For the character, see ??? (Character). For other uses, see ??? (Disambiguation).
**???** is the boss of Chest, accessed by defeating Isaac in the Cathedral while holding , which is always dropped by Mom after defeating Isaac five times. He is a posthumous version of Isaac, and the final boss of Ending 14.

## Behavior

??? lies on the ground in the middle of the room and does not begin attacking until he takes damage.

During all three of ???'s phases, he performs similar attacks to Isaac, but at a faster pace. He also shoots multiple projectiles in the player’s direction at fixed intervals. After taking enough damage, he begins to shoot double and triple projectiles.

* Each projectile has a chance of having a homing effect.

### Phase 1

??? remains stationary on the ground and performs the following attacks:

* Shoots 7-8 rapid-fire lines of projectiles in all directions that expand outwards. After taking enough damage, these lines curve while travelling.
* Shoots 8 lines of 2 projectiles in all directions that expand outwards. Each line consists of one normal projectile and one homing projectile. After taking enough damage, these lines curve while travelling.
* After taking enough damage, ??? summons Attack Flies, Moters, or Pooters that orbit around himself.
	+ Pooters have a farther orbit than the other flies.
	+ Attack Flies spawned from Moters chase Isaac instead of orbiting ???.

### Phase 2

2 Eternal Flies that can block tears begin to circle ???, who stands up but remains stationary and performs the following attacks:

* Continues to spawn orbiting flies.
* Fires 4 homing projectiles in a lop-sided X pattern.
* Fires 8 homing projectiles in all directions.

### Phase 3

??? grows a pair of angelic wings and is no longer stationary, slowing drifting towards Isaac and performing the following attacks:

* Spawns orbiting flies more frequently.
* Teleports to a position in front of Isaac- predicting his movements and attempting to cut him off. Teleports directly on top of Isaac if he isn't moving.
* Performs the 2 projectile patterns from the first phase.

## Gallery

* ??? in-game.
* ??? in his second phase.
* ??? in his third phase.
* ??? as one of  Delirium's forms.
* ???'s boss portrait in the GFVELLLL seed as well as the G Fuel themed daily challenge.
* ??? as a can of G Fuel.
* Trophy spawned after defeating G Fuel ??? in the daily challenge.
* ???'s old boss portrait prior to Repentance.

## Unlockable Achievements

* I RULE! -  Defeat **???** or The Lamb, defeat Satan as  Isaac, and unlock
 Defeat **???** or The Lamb, and defeat Satan as  Isaac
 Defeat Mega Satan and unlock .

* Backasswards -  Defeat **???** or The Lamb
 Defeat Mega Satan and unlock .

* Ultra Hard -  Defeat **???** or The Lamb. Possession of  /  is required, barring getting to Dark Room through a Sacrifice Room.
 Defeat Mega Satan and unlock .

* The D20 - Defeat **???** as  Isaac.

* Celtic Cross - Defeat **???** as  Magdalene.

* Cain's Eye - Defeat **???** as  Cain.

* The Left Hand - Defeat Ultra Pride as any character, or **???** as  Judas.

* Fate - Defeat **???** as  ???.

* Sacrificial Dagger - Defeat **???** as  Eve.

* Blood Penny - Defeat **???** as  Samson.

* Abaddon - Defeat **???** as  Azazel.

* Store Credit - Defeat **???** as  Lazarus.

* Mysterious Paper - Defeat **???** as  Eden.

* The Body - Defeat **???** as  The Lost.

* Cambion Conception - Defeat **???** as  Lilith.

* Deep Pockets - Defeat **???** as  Keeper.

* Locust of Famine - Defeat **???** as  Apollyon.

* Jaw Bone - Defeat **???** as  The Forgotten.

* Blessed Penny - Defeat **???** as  Bethany.

* Birthright - Defeat **???** as  Jacob and Esau.

* Something wicked this way comes! - Defeat **???** as 3 different Characters.

* Something wicked this way comes+! - Defeat **???** as 6 different Characters.

* Godhead - Earn all  5 /  9 (except Ultra Greed) /  10 /  12 Completion Marks on Hard mode as  The Lost.

* Mom's Lock - Defeat Isaac, **???**, Satan, and The Lamb as  Tainted Isaac.

* Holy Crown - Defeat Isaac, **???**, Satan, and The Lamb as  Tainted Magdalene.

* Gilded Key - Defeat Isaac, **???**, Satan, and The Lamb as  Tainted Cain.

* Your Soul - Defeat Isaac, **???**, Satan, and The Lamb as  Tainted Judas.

* Dingle Berry - Defeat Isaac, **???**, Satan, and The Lamb as  Tainted ???.

* Strange Key - Defeat Isaac, **???**, Satan, and The Lamb as  Tainted Eve.

* Temporary Tattoo - Defeat Isaac, **???**, Satan, and The Lamb as  Tainted Samson.

* Wicked Crown - Defeat Isaac, **???**, Satan, and The Lamb as  Tainted Azazel.

* Torn Pocket - Defeat Isaac, **???**, Satan, and The Lamb as  Tainted Lazarus.

* Nuh Uh! - Defeat Isaac, **???**, Satan, and The Lamb as  Tainted Eden.

* Kid's Drawing - Defeat Isaac, **???**, Satan, and The Lamb as  Tainted Lost.

* The Twins - Defeat Isaac, **???**, Satan, and The Lamb as  Tainted Lilith.

* Keeper's Bargain - Defeat Isaac, **???**, Satan, and The Lamb as  Tainted Keeper.

* Cricket Leg - Defeat Isaac, **???**, Satan, and The Lamb as  Tainted Apollyon.

* Polished Bone - Defeat Isaac, **???**, Satan, and The Lamb as  Tainted Forgotten.

* Expansion Pack - Defeat Isaac, **???**, Satan, and The Lamb as  Tainted Bethany.

* RC Remote - Defeat Isaac, **???**, Satan, and The Lamb as  Tainted Jacob.

## Notes

* ??? cannot teleport during his third phase if he is slowed (e.g. using ).

## Trivia

* ??? was added in the *Wrath of the Lamb* DLC for the original *The Binding of Isaac*.
* The music that plays during this boss fight is titled *Ascension*. The term "ascend" is typically used in religion as the act of one's soul rising to Heaven.
* ???, along with Isaac, flies away upon defeat and does not "die".
* ??? is commonly referred to as the 'blue baby' by the Binding of Isaac community, as well as Steam Achievements.
* ??? is fought as the first phase of  Hush with identical behavior and music, only using a different sprite. The Hush version also has half the HP.
* Delirium's ??? form is one of its only forms that don't have any melted features, along with both of the Angels.
* This is the posthumous version of Isaac.
* Blighted Ovum,  Big Horn, Triachnid, Isaac, and ??? are the only bosses whose portraits were completely changed in *Repentance* (beyond simply adding more detail). Of these, only Triachnid, Isaac, and ??? didn't receive new sprites.
	+ Isaac and ???'s portraits were changed to match their appearances on the transition screen between levels. This was also the case in the original Flash game.
* ??? has a unique sprite when encountered in the GFVELLLL seed as well as the limited time G Fuel themed daily challenge.
	+ This sprite was added in celebration of the release of "Isaac's Tears" flavored G Fuel.
* ??? Is also a reference to BlueBaby, Edmund's Newgrounds name.
* Blue Baby having literally blue skin color resembles Isaac suffocating in Chest.