Binding of Isaac: Rebirth Wiki

Disambig.png This article is about the boss. For the posthumous version, see Monstro II. For the enemy, see Ministro. For the item, see Lil Monstro.

Monstro is a boss that can appear in Basement Basement and the Added in Afterbirth Burning Basement Burning Basement.


  • Hops towards Isaac.
  • Coughs up a large number of disorganized projectiles towards Isaac.
  • Jumps off-screen, aiming to land on top of Isaac. Create a burst of disorganized projectiles in all directions on landing.

Champion Versions Needs to be unlocked[]

Grey: 15% larger and has 25% more HP (312.5). Uses projectile volleys much more often and is unable to jump off-screen.
Red: Two 20% smaller Monstros, each with 55% less HP than the original one (112.5), replace the normal Monstro.



Note: Layouts 1 and 11 are identical. Added in Repentance Layouts 8 and 9 no longer appear, as small boss rooms have been disabled.


  • In the boss room, Monstro can be paired with Black Flies, Attack Flies, Gapers, Hoppers, Frowning Gapers, Mulligans, Added in AfterbirthCyclopias, or Added in Afterbirth †Ministros.
  • When Monstro jumps off-screen, he is cured of all status effects.
  • Removed in Repentance Monstro can't hop over Obstacles.
    • If Isaac is somewhere that Monstro cannot reach, Monstro will jump in place.
    • If Isaac has flight and is over an obstacle, Monstro will essentially be unable to perform any attacks.
      • While Monstro can hit Isaac with his tear barrage because of its tear height, it is very unlikely.
  • Added in Afterbirth † Monstro can rarely spawn in a room with two Blood Donation Machines.
  • Added in Repentance Monstro will spawn in ??? ??? if IV - The Emperor? IV - The Emperor? is used. Defeating Monstro this way will count as defeating Hush for completion mark purposes.


  • Monstro appeared in the original The Binding of Isaac.
  • He is the boss version of the Added in Afterbirth † Ministros.
  • Monstro appears to be missing a tooth which happens to be an item.
  • Monstro is Monster in Portuguese.
  • Added in Repentance Monstro has a new fallback animation.