Mother's Shadow is a mini-boss found in a sub-area of the second floor of Chapter 2.5 ( Mines and Ashpit). It spawns on the way back after obtaining the Knife Piece 2. It's completely invincible and only serves as an obstacle in a chase sequence.
After entering the sub-area, all of Isaac's items, pickups, and trinkets are stripped away, leaving him similar to his state during the start of the game. He must walk through a couple of empty rooms before reaching the end room containing Knife Piece 2. Picking it up causes the room to shake and summons Mother's Shadow.
Mother's Shadow, after appearing, begins slowly floating after Isaac. When close enough to him, it stops and then quickly dashes at Isaac, dealing a whole heart of contact damage at all times. Isaac can 'push' Mother's shadow before its charge however and will not take contact damage. Mother's Shadow can go off-screen with its dash attack or when a door is crossed into a different room. It then resumes following Isaac.
- Mother's Shadow's position at all times is determined by its position relative to the general layout of the floor, meaning it persists in the same location even when Isaac moves through rooms. However, it cannot be left completely behind and is carried along as the screen moves.
- After encountering Mother's Shadow, the previously empty path back to the main floor map becomes filled with a variety of obstacles, some of which must be traversed past using Throwable Bombs from Bomb Grimaces, buttons, and sometimes keys and certain cards that spawn in each room.
As soon as Isaac passes the door leading out of the sub-area, Mother's Shadow screams Isaac's name in defeat and ceases to appear again, as the sub-area's entrance collapses and becomes blocked by falling rocks. It is no longer possible to enter the area again past this point.
- Upon acquiring the Knife Piece 2, all Fire Places are extinguished and then re-ignited as red fires as Mother's Shadow appears.
- Fire places can drop their pickups during this scene.
- Unlike non-story items, which disappear during the sequence, Isaac's health stays the same, and friendly enemies still follow him here.
- Extra lives granted by items such as Dead Cat or Guppy's Collar do not work, as they are removed from Isaac.
- Lazarus, however, still retains his extra life.
- Items that grant flight are taken away, forcing most characters to traverse the obstacles normally.
- The active piece of Broken Shovel will still spawn Mom's feet in this area.
- The key to avoiding damage during the chase sequence is to be patient. Trying to rush to the exit door will often result in unavoidable hits.
- Mother's Shadow will not attack Isaac directly between dashes, only move in his general direction. She will scream right before attacking, and will lock its direction; stay in place until she starts to dash and swiftly move out of the way.
- Going back into the previous room doesn't cancel its attacks, but provides more space for avoiding them, as well as invincibility frames.
- It is strongly discouraged to stand on one tile-wide paths for too long, because they limit Isaac's ability to move out of the way of its dashes.
- Since Isaac keeps any health he enters the area with, it is wise to stock up on hearts beforehand to minimize chances of death.
- Azazel, The Lost, Tainted Lost, Tainted Jacob in his Lost form, and Tainted Forgotten can escape with minimal risk, as they can fly directly to the exit door.
- The behavior and role of Mother's Shadow is similar to that of Phanto from Super Mario Bros. 2. In that game, it guards Keys and chases the player relentlessly if they pick one up. It only stops its pursuit if the Key is dropped or used to open a door.
- It is also potentially a reference to Pamela Voorhees in the Friday the 13th NES game, as both are flying heads with messy hair, and both attack the player by charging directly at them.
- If a Crawl Space or Black Market spawns, the player can regain access to their items and cards/pills/runes in that space; however Mother's Shadow will continue to give chase. If the player progresses to the next floor while in this space, Mother's Shadow dies, letting out the Isaac scream and temporarily locking the doors at the beginning of the next floor.
- Mother's Shadow resembles the face of Mom as she is depicted on the cover art for Repentance.
- Sometimes when charging, Mother's Shadow can yell Isaac's name in a deeper voice.
- The only items that are not taken away from Isaac in this sequence are Knife Piece 1, Key Piece 1, Key Piece 2 and Dogma, although the latter can only be obtained through special means.
- Blue Flies, Blue Spiders, Locusts, Cube of Meat spawned from a Potato Peeler, and Wisps spawned from Book of Virtues persist into this sequence but have no effect on Mother's Shadow. Blood clots spawned by Sumptorium will also persist and are immune to Mother's Shadow.
- Although Mother's Shadow has 250 health, it can not be damaged or killed, even with Chaos Card.
debug 10while entering the room containing Knife Piece 2 will kill Mother's Shadow before the chase activates. Picking up Knife Piece 2 will not start the chase if Mother's Shadow has been killed this way.
- Due to how the escape sequence is spawned (one version spawned when you enter for the first time, and one edited version spawned when Mother's Shadow appears after Knife Piece 2 is collected), items relevant to the escape sequence, such as cards used in puzzles like XII - The Hanged Man, will spawn both when the area is entered and when the escape sequence itself begins. Ergo, despite normally being blocked off, if you have some way to collect these items on the way to collect Knife Piece 2 (such as methods either as simple as using a character like Azazel or The Lost and their innate ability to fly, or complex ones such as using the explosive tears made by Wisps spawned from Book of Virtues combined with Bob's Rotten Head to break rocks that prevent items like these from being obtained on the first run through), you can obtain an extra copy of these items, allowing you to 'skip' rooms that may not account for you possessing these items before the escape begins - for example, using the aforementioned XII - The Hanged Man within the room you got it from before Mother's Shadow spawned to simply fly through the room, grab another copy of the same card spawned by Mother's Shadow's appearance before exiting, and then use that copy in another room.
- If Mama Mega! is used prior to entering the sequence, it will destroy all obstacles in every new room entered. However, due to how Mama Mega! works, it will not re-destroy obstacles on the way out, and thus does not aid the player during the chase.
- It will also have no effect on Mother's Shadow, as she spawns only when Knife Piece 2 is taken, and thus cannot be spawned before the blast.
|Bug!||If the game is saved and exited while in the sub-area, when it is continued, Isaac's visual appearance will match his items; however, items will still have no effect. It will revert to his plain appearance after either changing rooms or picking up a red bomb.|
|Bug!||Familiars with levels/stages will revert to their base form upon exiting the sub-area as the game does not internally store their levels. This includes, but is not limited to: Bumbo, Guppy's Hairball, etc.|
|Seven Deadly Sins||Envy • Gluttony • Wrath • Pride • Lust • Greed • Sloth|
|Super Sins||Super Envy • Super Gluttony • Super Wrath • Super Pride • Super Lust • Super Greed • Super Sloth • Ultra Pride|
|Devil/Angel Rooms||Krampus • Uriel • Gabriel|
|Repentance||Mother's Shadow • Dark Esau|
|The Binding of Isaac: Rebirth|
|Achievements||Attributes||Bosses||Cards and Runes||Challenges||Chapters|