Ashpit

The Ashpit is an alternative floor to the Mines and is unlocked by defeating all of the bosses inside the Mines. The floor can be accessed by using bombs on the Exit Door of the Caves/Catacombs/Flooded Caves I or II, or at the end of Downpour/Dross. Ashpit's theme is centered around a dry, crumbling wasteland, with an abundance of skeleton enemies and brutal-looking foes.

The Ashpit is significantly more difficult than their standard counterparts, filled with stone and bone-themed enemies that boast greater health and aggression. Most obstacles are rocks or spiked rocks, and Poops are almost non-existent. Tinted rocks have a high chance of spawning Tinted Rock Spiders. Travelling through it is only advised if you have already acquired Knife Piece 1 in Downpour and intend to access the Corpse.

After defeating the Mines II's boss, a door leading to the next alternate chapter - Mausoleum - appears. It requires 2 full hearts to open. The damage taken 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.

Unique Elements

Minecarts - Several rooms in the Ashpit will contain rail tracks with minecarts racing around on them, usually containing enemies or hazards. These enemies can be defeated as normal.
Throwable Bombs - Occasionally, you can find Bomb Grimaces with throwable bombs on the floor in front of them. You can pick up the throwable bomb by walking into it, lighting the fuse and giving you a few seconds to throw the bomb before it goes off. Once the bomb explodes, the Bomb Grimace will produce another, providing you with an unlimited source of bombs in these rooms.
Dark rooms - Some rooms are dark, even without the Curse of Darkness being active.

Monsters

Entity	ID	Description
Gurgle	87.0	Walks towards Isaac, dealing contact damage and periodically firing Ipecac shots at him; they are immune to this explosion, but other enemies are not. Can turn into a Splasher upon death.
Crackle	87.1	Walks toward Isaac, dealing contact damage and spitting fireballs that create lines of fire in the cardinal directions on impact.
Splasher	238.0	Walks aimlessly around the room, firing Ipecac shots in random directions.
Dragon Fly	25.3.0	Flies across the room in straight diagonal lines, dealing contact damage. Upon death, creates four lines of fire in the cardinal directions; the fire nearly spans the length of an entire normal-sized room.
Dragon Fly X	25.3.1	Flies across the room in straight diagonal lines, dealing contact damage. Upon death, creates four lines of fire in the ordinal directions; the fire nearly spans the length of an entire normal-sized room.
Bone Fly	25.4	Flies across the room in straight diagonal lines, dealing contact damage. Fires bones at Isaac if he lines up with it in the cardinal directions. Fires a radial burst of 3 bones upon death.
Hard Host	27.3	Stationary enemy that is normally invulnerable. Raises its head up when Isaac gets close, revealing a fleshy stem that can be damaged. Shortly after raising its head, it slams its head down and fires a rock wave towards Isaac.
Rock Spider	818.0	Slowly crawls around the room. If it sees Isaac, it crawls at him, trying to deal contact damage. Turns into a Spider upon death. Turns into a Coal Spider if it touches fire.
Coal Spider	818.2	Quickly crawls around the room. If it sees Isaac, it crawls at him, trying to deal contact damage. Turns into a hot coal upon death that blocks shots and deals contact damage, but can be destroyed.
Big Bony	830.0	Walks slowly toward Isaac, and will occasionally fire a bone that bounces around the room for a few moments. The bone can be broken if shot enough.
Stoney	302.0	Chases Isaac and blocks tears, but does not deal contact damage. Temporarily pauses in exhaustion after a certain amount of time. Invulnerable; dies when the room is cleared.
Pasty	881.1	Pops out of the ground and lunges toward Isaac, dealing contact damage and firing four shots in the ordinal directions.
Fly Bomb	819.0	Flies toward Isaac, circling around him as it does. Turn into a tiny Bomb upon death.
Flesh Maiden	880.0	Vaguely flies towards Isaac in curved swooping motions.
Death's Head	212.0	Invulnerable enemy that moves diagonally around the room, dealing contact damage. Dies when the room is cleared.
Dusty Death's Head	887.0	Invulnerable enemy that moves across the room in a waving motion in large quantities. Dies when the room is cleared.
Redskull	212.4	Moves diagonally around the room, creating a ring of fire around itself if Isaac gets close to it. Can be killed, but also dies when the room is cleared.
Blaster	821.0	Slowly wanders around and occasionally shoots Fly Bombs at Isaac.
Hardy	826.0	Dashes toward Isaac and deals contact damage creating rock projectiles when it hits a wall/obstacle. It spawns more rock projectiles the more times it crashes into obstacles, dying after doing so a third time.
Danny	820.0	Walks toward Isaac and spits chaotic bursts of rocks at him, some of which may be Rock Spiders.
Coal Boy	820.1	Walks toward Isaac and spits hot coals at him, some of which may be Coal Spiders.
Dust	882.0	Follows Isaac, and is only visible when close to Isaac. Will begin to speed up when they are visible. Teleports away after taking enough damage.
Clickety Clack	889.0	Walks towards Isaac and turn into a pile of bones when killed. Regenerates a few seconds after killed. Will only despawn if all Clickety Clacks in the room are killed.
Bombgagger	844.0	Spits up a Giga Bomb and runs away from it.
Necro	828.0	Stationary enemy that summons unlimited-ranged bones to attack Isaac.
Ink	61.3	Flies slowly towards Isaac. Fires four shots in the ordinal directions and leaves a puddle of slowing Black Creep upon death.
Bulb	61.5	Flies in erratic, angled movements toward Isaac if his active item has charges; on contact, they drain up to 2 charges, but never deal contact damage. If he has no active item, or no charges, they wander around the room aimlessly.
Carrion Princess	23.3	Slowly moves around the room, charging at Isaac when he lines up diagonally with it. Can only be damaged by hitting its tail.
Loose Knight	41.2	Moves erratically around the room, charges toward Isaac when in line of sight. When its health is depleted, it turns into a Brainless Knight and a Pon.
Migraine	869.0	Crawls around the room erratically, following Isaac and dealing contact damage. Can jump small distances. Releases multiple Troll Bombs upon death.
Bony	227.0	Wanders around the room and throws a bone at Isaac when he is in sight.
Black Bony	277.0	Wanders around the room and throws three bones in a row at Isaac when he is in sight. Explodes upon death.
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.
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.
Bomb Grimace	809.0	Stationary and invulnerable monster that keeps a single Throwable Bomb spawned.
Quake Grimace	804.0	Stationary and invulnerable monster that jumps and fires a line of rocks in one direction upon landing.
Wall Hugger	218.0	Moves around the room like Guts, damaging Isaac by contact. Cannot be destroyed.

Bosses


The Pile	The Shell	Great Gideon	Singe

Clutch

Knife Piece

If you have Knife Piece 1, a special double-sized room will spawn in Mines II containing a minecart and a broken length of rail track leading to a boarded up door, just like those that lead to a Bedroom. Behind this door lies the area in which Knife Piece 2 can be acquired. There are two methods for accessing this area:

If you have flight and 2 Bombs, you can simply fly over to the boarded up door and blow it open. It is also accessible with flight and a item with an effect that opens doors such as Dad's Key, Soul of Cain, Cracked Orb, etc.
Otherwise, you can repair the track. There are three yellow buttons spread throughout the floor. One will be in the same room as the broken rail track, but the other two are randomly placed. Once all three buttons are pressed, the rail track will be repaired and you can touch the minecart to access the area.

Upon entering this area, all passive and active items will be rendered inactive, and your Bombs, Coins, and Keys will be set to zero. New pickups can still be obtained, however, and will persist after Isaac leaves the area. You will pass through several empty rooms before reaching a room with the Knife Piece 2. Once you pick it up, Mother's Shadow will spawn and your race back to the entrance begins. This enemy cannot be defeated by any means, and escape is your only option.

Unlike your initial trip to reach the Knife Piece 2, the path back will be obstructed by rocks and Poops. While flying characters can handle all of this with ease, walking characters will have a significantly harder time. Using your tears and the conveniently-located Throwable Bombs, you will need to break through the obstructions, press buttons, and grab keys for key blocks to make it back to the main dungeon. Making it out taking little or no damage is possible, particularly if you are fast and accustomed to dodging the shadow's attacks. Once you escape, all your items will be reactivated, and the shadow will end its pursuit.

It is possible for the floor's Crawl Space to appear on your escape path. Upon entry, your items will temporarily be reactivated, and you will be able to pick up any items/consumables available. Items will become inactive again after exiting. Mother's Shadow will still appear in the crawl space, and the enclosed area makes the dodging of her attacks very difficult. Furthermore, if a key is required to complete an obstacle on the way back, and it is picked up before entering the crawl space, it will be lost and could make the obstacle impossible.
- The Black Market can also appear in a crawlspace. Entering the trapdoor will complete the escape sequence.