Curses

Every floor Isaac reaches has a chance to be **cursed**, which hides or alters game elements to make the floor more difficult to complete. Each curse only lasts for the current floor. The possible curses are:

 **Curse of Darkness** | The floor is much darker, and is only barely lit by Isaac's natural aura. Rooms are occasionally filled with swarms of intangible glowing particles. Fire, explosions, and lasers will all cast light as normal, as will red creep.
 **Curse of the Maze** | Entering a new room (including teleporting) will occasionally take Isaac to the wrong room, with a screen-shake and sound effect to indicate the jump. For example, entering the room on the right may instead take Isaac to the room on the left. Occasionally, discovered rooms with identical door layouts can swap contents, without a screen-shake or sound effect.
 **Curse of the Unknown** | Removes Isaac's health from the HUD, leaving the player unable to see how many hearts remain of any kind. All health is still be tracked as normal, and Isaac still urinates on the floor by the door when he enters a room at half a heart of total HP.
 **Curse of the Giant** | Merges normal-sized rooms into 2x2, 1x2, 2x1, or L-shaped rooms while narrow rooms are not affected*(further confimation needed)*. This curse currently isn't achievable naturally in game.

## Chance

Odds of getting a curse vary with progression, increasing over time.

 Killed Mom | 1/30
 Everything is Terrible
 Killed Isaac | 1/5

* All curses have an equal, 1/6 chance of occurring.
	+ If Curse of the Labyrinth is picked on a floor it cannot spawn on, such as the second floor of any chapter, Greed Mode, or on any chapters post-Womb, no curses will be active for the floor.
		- This makes the chance of getting cursed on floors without Curse of the Labyrinth 1/6, or  5/12 or  5/18 for Hard Mode if Isaac has been defeated.

## Notes

* **Curse of the Labyrinth** can spawn the same boss in both rooms on one floor.
* If **Curse of the Labyrinth** is encountered in Basement, Cellar, or the Burning Basement, both Treasure Room doors will be unlocked.
* Because Curse of the Labyrinth causes the two floors in a chapter to merge, the Devil Room can be encountered in Basement I, Cellar I, or Burning Basement I, and the chances to do so are lowered as usual if Isaac takes red heart damage.
* With the Curse of the Labyrinth, it is possible to teleport into the second Boss Room and completely skip the first.
* If Curse of the Labyrinth takes effect during Chapter 1, taking the door that spawns after the second boss room will lead to Downpour II or Dross II.
* If Curse of the Labyrinth merges Downpour or Dross, there will be two "mirror" Boss Rooms.
* If Curse of the Labyrinth merges Downpour, Dross, Mines, or Ashpit into an XL floor, the special rooms leading to  and , and their associated gimmicks, will still appear.
	+ Only one of the "mirror" treasure rooms in Downpour and Dross will contain the knife piece; the other will be empty.
* **Curse of Darkness** can be made somewhat easier by increasing the gamma setting in the game's options.
	+ can now remove Curse of Darkness for the current floor.
	+ The  can remove Curse of Darkness for the floor it's picked up. While it does not make Isaac immune to the Curse in floors after picking it up, the light beam it emits diminishes the drawback of low visibility.
* **Curse of the Unknown** does not affect  The Lost, as he is, technically speaking, perpetually under its effect anyways.
	+ The Lost can no longer see whether the 's shield has been broken in the current room.

* **Curse of the Maze** can be exploited to enter all types of locked rooms without spending resources. Be warned, though, as trying to enter a Curse Room can teleport Isaac elsewhere, dealing damage without getting him into the desired room (unless he has some form of flight).
* When Curse of the Maze triggers, it takes into account the direction the room was exited through. For example, if Isaac leaves a room by a door on the right wall, it can only take Isaac to a room that has a door on its left wall. (This also works with teleporting.)
* Since Curse of the Maze can only swap rooms with identical door layouts, if one of the rooms has a wall where the other had a door, a secret room is guaranteed to be there.
* Curse of the Maze may otherwise interfere with teleportation cards, but  is unaffected.
* With Curse of the Maze active, using any form of extra life or revival item can put Isaac into a previously unvisited room.
* Curse of the Maze can teleport Isaac to the same room he was just in.
* Items that reveal the entire map do not counteract the effect of Curse of the Lost.
* With **Curse of the Blind** active, leaving and re-entering a room which had a revealed item will change the item back to a question mark.

3DS Curse of the Lost can be countered, as the player can draw a map on the touch screen.

## Trivia

* Of the three curses that returned from *Wrath of the Lamb,* (Labyrinth, the Lost, and Darkness), two of them — **Curse of the Lost** and **Curse of Darkness** — have different effects from *Rebirth* onwards.
	+ The Curse of Darkness used to hide the map, but was given the floor darkening effect in Rebirth.
	+ The Curse of the Lost used to simply add 4 floors to the possible total room count of a floor, and was also given the map removal effect from Curse of Darkness.
	+ The **Curse of the Labyrinth** remained untouched.
* **Curse of the Giant** originated from the *Antibirth* mod, but cannot be encountered in-game without using mods or the Debug Console. This was because the room-combining aspect of the curse would often lead to buggy or unfair rooms.
	+ A system was to be added that determined the fairness of a large room, such as limiting the number of enemies, but this proved to be too complicated to finish in time.
* There is another curse being used internally in the game, called **Curse of the Mist**. This is active inside the Mother's Shadow area and is used to disable Isaac's items.