To unlock The Lost in the Afterbirth / Afterbirth Plus version of The Binding of Isaac, let yourself be defeated at any slaughter room (sacrifice room, the one. Die to your own bombs in The Caves or Catacombs as Magdalene. Method 1 of 2: Rebirth Download Article Die to a Mulliboom in the Basement or Cellar as Isaac. To unlock Missing poster you have to defeat boss The Lamb as. The Lost is unlocked by dying in a Sacrifice Room while holding Missing Poster. Being killed by any monster spawned by Mom will spoil the entire attempt at unlocking The Lost. How to Unlock THE LOST in Binding of Isaac Rebirth | Isaac, Rebirth, Binding Magdalene must die to her own bomb in Chapter 2. Isaac must die to a Mulliboom in Chapter 1.
