The Chest

The Chest is one of the final levels in The Binding of Isaac, alongside the Dark Room and The Void.

The Chest can be accessed with three methods: Touching the chest dropped by Isaac while having The Polaroid (always dropped by Mom after beating Isaac five times) equipped, or, while in the Cathedral, by using Telepills or another item that acts like Telepills, and being sent to the I AM ERROR room, or finding a Black Market on the Cathedral and going into the beam of light.

Like the Cathedral before it, The Chest consists of only one floor. In The Chest, it is not possible to bomb doors open to skip rooms. The Chest's rooms are mainly filled with bosses and mini-bosses. The boss of the floor is always ???.

The first room in The Chest will automatically contain 4 golden chests. These special chests always contain Treasure Room Items. Additionally, all brown and golden chests spawned in The Chest will always contain Treasure Room Items. This means that a lot of different items can be found in The Chest when clearing rooms with items or effects that raise the chance of spawning chests. This can be useful when trying to complete your Collection Page.

After completing The Chest or the Dark Room for the first time, the first room of The Chest will always contain a large golden door, which can be unlocked with either the Key Pieces (combination of Key Piece 1 and Key Piece 2), Dad's Key, Get out of Jail Free Card or Mr. ME!, allowing access to Mega Satan.

Completing this level without getting hurt grants the Dead Boy achievement.

Monsters

Monsters	Description
Attack Fly	Red fly that follows Isaac and deals touch damage.
Bony	Wanders around the room and throws a bone at Isaac when he is in sight.
Dip	Slowly dashes in random directions, dealing contact damage.
Dinga	Slowly moves around the room, occasionally hopping, spawning Dips or firing 8 brown shots in all directions. Spawns 2 Squirts on death.
Frowning Gaper	Walks towards Isaac, dealing contact damage. Upon getting near Isaac, it will open its eyes and pursue Isaac faster. Usually turns into a Pacer or a Gusher upon death.
Lil' Haunt	Follows Isaac erratically and occasionally shoots blood shots toward Isaac's destination, predicting his movements.
MemBrain	Slowly moves around the room, occasionally hopping and firing 8 large blood shots in all directions. Splits into 2 Brains upon death.
Oob	When Isaac lines up with it horizontally, it charges across the room once. When Isaac is not horizontal to it, it spawns Brains.
Pale Fatty	Slowly walks towards Isaac. Occasionally farts and shoots blood shots in 6 directions. Can turn into a Blubber upon death.
Spider	Erratically moves towards Isaac and deals touch damage.
Slide	Quickly slides towards Isaac when he gets in its line of sight, then moves slowly back to its original position. Cannot be destroyed.
Blue Conjoined Fatty	Slowly walks towards Isaac and occasionally farts out a homing Ipecac shot at Isaac.

Boss

???

Notes

• If Isaac gets Key Piece 1 and Key Piece 2, the key will open the golden gate to fight Mega Satan, but if Isaac uses Forget Me Now, the floor will reset and Isaac won't get both Key Pieces back, making it so that the golden gate won't open again.
• It is possible to create trapdoors thanks to Normal Buttons (found for example in a Secret Room). Upon entering them the floor is restarted. If the large golden door was opened before restarting, it will be closed afterwards.
• The I AM ERROR room cannot be reached by any method in The Chest and the Dark Room.

Unlockable Achievements

• 

  Angels - Complete Chapter 6.

• 

  Dead Boy - Complete chapter 6 without taking damage.

• 

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

• 

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

Trivia

• The music for the chest is titled Sketches of Pain.
• The Chest and its boss, ???, are based on the in-game backstory of Isaac locking himself in his toy chest and asphyxiating to death.
• The sprite appearance of ??? is a reference to Edmund McMillen's Dead Baby games, which are often referenced throughout The Binding Of Isaac.
• The texture of the floor may have a small chance of showing two small glowing dots which look like eyes.
• Like in the Dark Room, bombing the doors to open them doesn't work on this floor.
• The shadow cast on the floor most likely resembles Isaac's head while opening the chest.