Binding of Isaac: Rebirth Wiki

Added in Repentance

Knife Piece 2 is a passive item added in The Binding of Isaac: Repentance.


  • Combines with Knife Piece 1 Knife Piece 1 to form a knife familiar that launches itself in the direction Isaac shoots, dealing 25 damage to and piercing enemies it hits.
  • Launching it at the red door at the end of Mausoleum Mausoleum/Gehenna Gehenna II will open the door, destroying the knife in the process.

How to Acquire[]

  • In Mines Mines/Ashpit Ashpit II, there is a tall room with a broken minecart track. Scattered across the floor are three yellow buttons that will repair pieces of the track. Once all buttons have been pressed, the minecart becomes rideable, which will take Isaac to an abandoned area, with Knife Piece 2 at the end. Picking up the Knife Piece will trigger a chase sequence in which Mother's Shadow Mother's Shadow will pursue Isaac through the corridor. Getting to the end of the area will seal it off.


  • While in the abandoned area, all of Isaac's items and consumables are removed. Extra Life items will not activate despite still visually appearing beside the health bar. However, any items with reroll protection will still function as normal. (This includes Knife Piece 1 Knife Piece 1 itself.)
  • This room, as well as the buttons to reach it, will only be generated if Knife Piece 1 was already collected.
  • The buttons can be bypassed with flight and 2 bombs to destroy the door. Upon exiting the room, the rail pathway will be built in order to prevent softlocks from using temporary flight methods such as The Bible The Bible.
  • If Isaac takes Knife Piece 2 and is somehow able to immediately leave the room before Mother's Shadow Mother's Shadow fully activates (usually by using Mama Mega! Mama Mega! earlier in the floor), the rest of the sub-area will not have reset, and the doors leading to the exit will all be locked. This forces the player to re-enter the Knife Piece 2 room, which triggers another activation of Mother's Shadow Mother's Shadow, causing two instances of Mother's Shadow to pursue the player during the escape sequence.
  • It is possible to find a crawlspace as normal in this area, which will be the same crawlspace as any other generated on the normal floor. Entering the crawlspace will allow Isaac to use his normal items and consumables, but Mother's Shadow will also be present. Using any teleport card or item will teleport Isaac to a random room on the abandoned area map. Any items obtained while in this crawlspace will remain upon leaving the area, but will not be able to be used while in the abandoned area.
    • It is possible to softlock the run by entering a crawlspace with the key needed to escape the room. Upon leaving the crawlspace, the key will be gone.
    • Black market can be entered from the crawlspace. Going through the trapdoor there will end the pursuit and lead to Depths I (or alternatives). Isaac will keep all his items, including those bought in the market.
  • Unlocking the door to get to the Mausoleum version of Mom's Heart Mom's Heart consumes the knife familiar.
  • It's possible (though useless) to acquire another Knife Piece 2 using Forget Me Now Forget Me Now and R Key R Key.