Gehenna

Gehenna is an alternative floor to the Mausoleum and was added in The Binding of Isaac: Repentance.

Gehenna has a demonic theme, with horned skulls, bones, and blood on the black cracked floor, while bloodied chains hang from the walls. Unique features of this stage include Teleporters, Grudges, and the Ball and Chain.

The door to the Mausoleum / Gehenna will appear after defeating the boss in The Mines II / Ashpit II or the Depths I / Necropolis I / Dank Depths I. The door will not spawn after defeating Mom. It costs two full hearts to enter, and ignores almost every form of damage reduction, including The Wafer and invincibility. Unlike other methods of health donation, red hearts will not be prioritized over more valuable hearts.

The Lost, Tainted Lost, Tainted Jacob (In his soul form), Tainted Soul (unless he is holding Tainted Forgotten), and any character under the effect of Soul of the Lost can enter the door for free.
Dad's Key, Get out of Jail Free Card, Mr. ME!, and Sharp Key can be used to open the door without taking damage.
Broken Padlock can be used to open the door with one bomb.
Cracked Orb's effect can open the door with less damage taken than needed, or with no damage with Dull Razor.
The extra characters spawned by Strawman, Soul of the Forgotten, and Soul of Jacob and Esau can expend their health to open the door.
Crow Heart can be used to open the door with red hearts first.

The boss of Gehenna II is always a more powerful version of Mom. After Mom is defeated, a trapdoor that leads to the Womb II, and a sealed fleshy door both appear. Stabbing the door with the knife familiar created by Knife Piece 1 and Knife Piece 2 will cause it to open, leading to a more difficult version of Mom's Heart. Defeating Mom's Heart will cause the boss room to darken, and the trapdoor to Womb II will now lead to the Corpse.

A Sharp Key can be used in place of the Knife.
Cracked Orb's effect can open the flesh door, allowing Isaac to keep the knife.
If Isaac exits the Boss Rush room after 25 minutes have passed, there is a chance that the flesh door will change positions to the wall where the boss rush door was, causing Isaac to "come out" of the flesh door and leaving it open, allowing entry without the knife.
After this special version of Mom's Heart is defeated, any Item or Pickup that was left behind anywhere on the floor will disappear (including Shop items, Angel Room/Devil Room items, etc.): the floor will be empty.
- Therefore, make sure not to leave behind something that you might want to use after this floor. The strategy consisting in teleporting outside of Mom and Mom's Heart to retrieve something that was left behind after fighting them is not viable here.
- The Boss Rush entrance will disappear if it was previously open.
- If a Shop Restock Machine is used within the now-empty shop, it will restock the shop as normal.
- If the effect of Forget Me Now is invoked after the special version of Mom's Heart is defeated, the Curse of Darkness-like effect will remain on the newly generated floor. Additionally, no items will naturally generate in rooms where they would have. After the player defeats Mom again, there will be no flesh door, and the trapdoor to Corpse will appear.

Monsters

Entity	ID	Description
Baby Begotten	883.0	Floats toward Isaac, avoiding his shots. After getting close, fires a short Brimstone laser in the closest cardinal direction and propels itself away from him.
Begotten	251.0	Starts attached to the wall or an obstacle. After a while, it detaches, firing 6 blood shots in all directions, turning the room dark, becoming invisible and chasing Isaac. Briefly becomes visible upon getting hit.
Goat	891.0	Wanders around the room. Occasionally moves toward Isaac, either firing blood shots at him or charging if he lines up on either side of it.
Black Goat	891.1	Wanders around the room. Occasionally moves toward Isaac, either firing blood shots at him or charging if he lines upon either side of it. Can also fire thin Brimstone lasers in the cardinal directions, along with all other Black Goats in the room.
Cultist	885.0	Creates an indestructible, homing Purple Ball at the start of the room and follows it around, occasionally leaving it to revive enemies that have died in the current room.
Blood Cultist	885.1	Wanders around the room and fires a line of blood shots and creep if Isaac is on either side of it. Can summons bone traps that temporarily ensnare Isaac if he walks into them.
Bony	227.0	Wanders around the room and throws a bone at Isaac when he is in sight.
Revenant	841.0	Slowly wanders around the room, stopping to fire a large line of fire at the player.
Quad Revenant	841.1	Wanders around the room slowly, stopping to fire lines of flames in the cardinal or ordinal directions, rotating in an attempt to hit Isaac.
Maze Roamer	890.0	Wanders around the room and shoots an eyeball at Isaac when he is in sight. Has a clone of itself on the other side of the room that mimics its movement and shots. If one dies, the other starts actively pursuing Isaac.
Dople	53.0	Mirrors Isaac's movements and fires blood shots at the same time as Isaac. Can be damaged by spikes.
Death's Head	212.0	Invulnerable enemy that moves diagonally around the room, dealing contact damage. Dies when the room is cleared.
Brimstone Death's Head	212.3	Invulnerable enemy that moves diagonally around the room, pausing to fire a Brimstone laser when Isaac lines up with it in the cardinal directions. Dies when the room is cleared.
Vis Fatty	886.0	Spawns with a Fetal Demon attached to it and slowly walks towards Isaac. Will occasionally fart, briefly pushing the demon away and spawning creep around itself and the demon. If the demon is killed first, the Fatty will shoot out Brimstone in the diagonal direction closest to Isaac. It will then fly around the room diagonally, bumping off of walls and tall blocks, all while continuously firing Brimstone behind it.
Fetal Demon	886.1	Usually encountered tethered to Vis Fatties. When tethered it makes short lunges towards Isaac if he gets close. If the Vis Fatty is killed or when encountered alone, it will chase Isaac, similarly to Gemini's Suture.
Fly	13.0	Hovers in place. Does not deal contact damage and is harmless, but can turn into Pooters if they stay around Poop.
Eternal Fly	96.0	Invulnerable fly that circles Corny Poop and various monsters. Deals contact damage. Turns into a vulnerable Attack Fly after the object or monster it circles is destroyed.
Sucker	61.0	Flies slowly towards Isaac, exploding into 4 shots in the cardinal directions upon death.
Soul Sucker	61.2	Flies slowly towards Isaac. Spawns a vortex that fires four Brimstone beams in the cardinal directions upon death.
Whipper	834.0	Runs around the room, sprinting at Isaac when he gets in its line of sight and lashing at him when it gets close.
Snapper	834.1	Runs around the room, sprinting at Isaac when he gets in its line of sight and throwing out its whip when he gets in range.
Cursed Globin	24.3	Chases Isaac, dealing a full heart of contact damage. Upon taking enough damage, it collapses into 1-2 piles of goo, each of which can be killed and regenerate after a short period of time if not killed quickly. These goo piles have less health the more times the Cursed Globin splits.
Black Knight	41.4	Moves erratically around the room, charges toward Isaac when in line of sight. Unleashes waves of fire in all cardinal directions upon charging into an obstacle. Shots that hit it from the front are deflected back at Isaac.
Mask + Heart	93.0	The Mask is invulnerable and moves around erratically, charging at Isaac when he lines up with it. The Heart avoids Isaac and fires 4 blood shots in the cardinal directions when Isaac gets near. Killing the Heart will automatically kill the Mask.
Mask II + 1/2 Heart	93.1	The Mask is invulnerable and moves around erratically, charging at Isaac when he lines up with it. The Heart avoids Isaac and fires 4 blood shots in the ordinal directions when Isaac gets near. Killing the Heart will automatically kill the Mask. If there are more than one 1/2 Heart in the room, they will fire blood shots between each other.
Big Spider	94.0	Erratically moves around the room. If Isaac gets close to it, it chases him, trying to deal contact damage. Spawns two Spiders upon death.
Poofer	892.0	Slowly floats toward Isaac, swells up and fire 6 blood shots in all directions upon taking damage. Explodes upon death, healing nearby enemies and leaving a big puddle of red creep.
Vis Versa	836.0	Randomly wanders around the room. Pauses to charge and fire a homing Brimstone laser when Isaac gets in its line of sight.
Lil Portal	306.1	Spawns fly and spider enemies until it is destroyed.
Morningstar	863.0	Floats toward Isaac to deal contact damage while Isaac is moving, gaining speed the longer Isaac continues moving. Stops moving when Isaac stops moving.
Mockulus	864.0	Invulnerable enemy that rapidly floats diagonally over obstacles and bounces off of walls, blocking tears and dealing contact damage. They can only move while Isaac is shooting.
Poky	44.0	Slides around the room aimlessly, damaging Isaac by contact. Disappears when the room is cleared.
Wall Hugger	218.0	Moves around the room like Guts, damaging Isaac by contact. Cannot be destroyed.
Grudge	877.0	Quickly slides towards Isaac when he gets in its line of sight. Cannot be destroyed.
Ball and Chain	893.0	Spike balls that rotate at the end of a chain attached to an obstacle. If the obstacle is destroyed, the ball will fly free around the room for a while.
Stone Grimace	42.0	Stationary and invulnerable monster that occasionally fires a blood shot at Isaac. Stops firing when room is cleared.
Vomit Grimace	42.1	Stationary and invulnerable monster that occasionally fires an Ipecac shot at Isaac. Stops firing when room is cleared.
Triple Grimace	42.2	Stationary and invulnerable monster that occasionally fires a triple shot at Isaac. Stops firing when room is cleared.
Brimstone Head	203.0	Stationary and invulnerable monster that fires Brimstone beams in a specific direction.
Gaping Maw	235.0	Stationary and invulnerable monster that sucks Isaac towards it, along with Isaac's tears and enemy projectiles.
Broken Gaping Maw	236.0	Stationary and invulnerable monster that sucks Isaac towards it, along with Isaac's tears and enemy projectiles. Alternates between active and inactive every couple of seconds. Has a stronger attraction power than a regular Gaping Maw.
Constant Stone Shooter	202.0	Stationary and invulnerable monster that continuously fires shots in a single direction.
Cross Stone Shooter	202.10	Stationary and invulnerable monster that continuously fires shots in four directions, alternating between cardinal and ordinal.

Degraded Bosses:

Name	ID	Notes
Dark One	267.0

Bosses


The Visage	The Horny Boys	Mom	Mom's Heart

Trivia

In Hebrew belief, Gehenna (or Gehinnom) was thought to be a small valley in Jerusalem. The name literally translated to "Valley of Hinnom" and in the Valley, Kings of Jerusalem would sacrifice their children through fire.
- Gehenna was also thought to be "the destination of the wicked" in Jewish literature. It differs from the neutral-leaning Sheol as Gehenna was considered a type of waiting room; the longest one can be there is 11 or 12 months with few exceptions.
- It was also thought to be the location of Jerusalem's garbage dump, where the city's waste and the corpses of criminals were disposed by incineration. These fires burned for most of the day, inspiring later descriptions of Hell as a place of eternal torment by fire for the wicked.
This floor may a reference to The 7 Planes of Hehenna, a similarly named area in another of Edmund McMillen's games, Gish. This is reinforced by the numerous similarities the two share, such as the appearance of gimp-clad enemies and the visual theme of a demonic temple.
- The boss Sisters Vis was also originally the boss of this area in Gish, though that is not the case for Gehenna.
As the Mausoleum only has 2 unique bosses, it is possible to unlock Gehenna in one run by completing a Boss Challenge room in Hard mode, as both bosses will spawn.

Music

The music in Gehenna is titled Morning Star.
- "Morning Star", "Shining One" or "Light-Bringer" comes from ancient greek and is used to refer to Lucifer.
- The planet Venus is considered the Morning Star and is associated with the Devil falling from heaven. This is due to it falling beneath the horizon in the morning, much like how the former angel fell to Earth. Venus and the Devil share the name Lucifer because of this.
- A morning star is also a type of weapon that consists of a spiked ball at the end of a club. An extremely brutal weapon that also resembles the rotating spike balls and the similarly named enemies unique to this floor.
In the background of the track, the Latin phrase "bonum est Deus" can be heard, which can be translated to "God is good."