Binding of Isaac: Rebirth Wiki

Crawl SpaceCrawl Spaces (also known as Retro Treasure Rooms) are small secret rooms that can be entered by touching trapdoors with ladders in them. They can be found by:

  1. Using Collectible We Need To Go Deeper! iconWe Need To Go Deeper! (except in Repentance) randomly (8% chance)/(in Repentance) on certain patterned tiles (100% chance once per floor)
  2. Using Rune of EhwazRune of Ehwaz (except in Repentance) randomly (10% chance)/(in Repentance) on certain patterned tiles (100% chance once per floor)
  3. Bombing a Clean BedroomClean Bedroom rug (100% chance)
  4. Destroying a rock (see below)
  5. (in Repentance) Using Chaos CardChaos Card on Boss Great Gideon ingameGreat Gideon (100% chance)
  6. (in Repentance) Using XXI - The World?XXI - The World? (100% chance)

These rooms are viewed from the side, rather than from above like the rest of the game, and Isaac will experience gravity pulling him to the floor while he is not walking on top of one of the ladders. Under the effects of flight, this gravity has no effects. However, Isaac cannot fly over the walls or floor. Items spawned inside are generated from the Treasure Room Item Pool.

Mechanics[ | ]

When entering a room pre-determined to contain a Crawl Space entrance, an RNG roll is made using the floor seed. This value will be shifted and divided, until its final result is in the grid range for the current room (ie: 128 tiles for 1x1 rooms, or 16x8). If said tile value is tied to a simple rock (not tinted, not a prop), then access to the Crawl Space will be granted upon destroying that rock. Only one room per floor has the right to spawn a Crawl Space, and not every floor is given one during the initial generation, even though every floor has also a Crawl Space and a Black Market ready in queue. The tile value can also be tied to props (empty tiles, doors, pots, void tiles, spikes, metal blocks, ...), but the Crawl Space won't spawn unless it's below a simple rock.

  • This makes the rocks contained in (except in Rebirth)?????? have a significantly increased chance of spawning a crawl space.
  • (in Repentance) Crawl spaces may spawn under variants of rocks.

Layouts[ | ]

Downward arrows represent tiles where no ladder is present, meaning Isaac will be forced downward toward the floor. This is also true of tiles that contain pickups.

Notes[ | ]

  • Crawl Spaces sometimes contains another exit on the right side, which leads to a Black MarketBlack Market.
  • There is only one Crawl Space room per floor. Thus, if Isaac finds two trapdoors with ladders on the same floor, they will lead to the same Crawl Space. When Isaac exits the Crawl Space, he will come out from the entrance he came in from. (in Repentance) Creating a Crawl Space within a Crawl Space with XXI - The World?XXI - The World? will just take Isaac back to the original one.
  • Entering a Crawl Space in the Boss RushBoss Rush room and exiting it after the time limit has expired will transport Isaac back to the Boss Mom ingameMom Boss room.
  • There is no map in the Crawl Space, similar to the Black MarketBlack Market, the I AM ERRORI AM ERROR room, the Devil RoomDevil Room, and the Angel RoomAngel Room.
    • This is because the Crawl Space does not technically occupy a fixed location on the floor relative to other rooms; Isaac is, in a sense, teleported to the Crawl Space when he touches the trapdoor. Possibly related to this, should Isaac enter a crawl space from a Devil Room, upon exiting he will emerge back in the regular map.
  • Be careful when using Collectible The Poop iconThe Poop, as in certain situations, The Poop can block the exit and trap Isaac.
  • Crawl spaces can appear in Greed mode as well.
  • (except in Repentance)It is possible to enter Black MarketBlack Markets through a Crawl Space even when there is no path to it. By using two bombs, Isaac can clip out of bounds and then walk underneath the Crawl Space room.
    • (in Repentance) Leaving a Crawl Space from any side where no exit exists brings Isaac to I AM ERRORI AM ERROR instead. It is now significantly more difficult to clip out of bounds, and can't be done with just two bombs.
  • (except in Rebirth) With Collectible Continuum iconContinuum, if Isaac shoots downward in a Crawl Space, his tears will continuously accelerate and may loop many times (over 20), regardless of his range.
  • (except in Rebirth) Rocks with Crawl Spaces under them will flash while holding the Shiny RockShiny Rock.
  • (except in Rebirth) The trinket Stud FinderStud Finder adds an additional 1 in 200 chance for a Crawl Space to appear when a rock is destroyed.
  • (in Repentance) The Crawl Space that appears by using a Chaos CardChaos Card on Boss Great Gideon ingameGreat Gideon always has the same design even if another Crawl Space was encountered.
  • (in Repentance) One Crawl Space layout contains two items, one of which is entirely enclosed by walls. The following are ways to obtain the seemingly off-limits item:
    • Teleport to it with Collectible Stitches iconStitches;
    • Grab it with Collectible Mr. ME! iconMr. ME!;
    • Jump through the wall with Collectible How to Jump iconHow to Jump;
    • Using Collectible Void iconVoid with Collectible Birthright iconBirthright when playing as Character Apollyon iconApollyon has a 10% chance to create a copy of the item after being absorbed by Void;
    • Absorb it with Collectible Moving Box iconMoving Box, then place it in another room;
    • Clipping through the wall with Collectible Pluto iconPluto;
    • Cloning the item using Collectible Diplopia iconDiplopia and grabbing the copy created underneath.
    • Entering the crawl space during the Ascent. The room layout is a little different, and the item will no longer be blocked off; there may be a Shop Restock MachineShop Restock Machine.
  • (in Repentance) Crawl Spaces can be found during the Mother's ShadowMother's Shadow sequence. She will follow Isaac into them, so care must still be taken to avoid her charge.
    • (in Repentance) The sequence may contain key blocks, usually with a key nearby. If a key is in your inventory when entering the crawl space, it will get transferred to your key pool, rendering a nearby keyblock impossible to remove.
  • Crawl spaces can still be found on floors during the Ascent to HomeHome.

Gallery[ | ]

Trivia[ | ]

  • The layout of the Crawl Space is a direct visual reference to the treasure rooms in the Legend of Zelda for the NES.
  • Crawl Spaces are referred to within the game files as "Item Dungeons".

Bugs[ | ]

Bug Bug! If Isaac's hitbox is small enough (by using One Makes You Smaller pills), it's possible to travel through the walls and ceiling to access the Black MarketBlack Market. In the walls are much harder to clip through, but it can still be done with high speed and help of the stairs or flight.

Bug Bug! If Isaac uses a XXI - The World?XXI - The World? card inside a Black MarketBlack Market and enters it, he will be taken to the crawl space that leads to the Black Market. If he then tries to leave the crawl space from here, he will be spawned back inside it making exiting to the main floor no longer possible. If this is done on the ChestChest, Dark RoomDark Room, The VoidThe Void, or HomeHome floors it will result in a soft lock since Isaac cannot leave through the trap door that usually spawns in the Black MarketBlack Market.

References[ | ]

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