Binding of Isaac: Rebirth Wiki
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.

Bosses Boss Monstro.png
Chapter 1
Stage Basement icon.pngStage Cellar icon.pngStage Burning Basement icon.png
GeminiStevenBlighted OvumDingleThe Duke of FliesFamineGurglingsThe HauntLarry Jr.MonstroPinWidowThe FallenThe Headless Horseman
DangleLittle HornRag ManTurdlings
Baby Plum
Chapter 1.5
Stage Downpour icon.pngStage Dross icon.png
Lil BlubWormwoodThe RainmakerMin-MinClogColostomiaTurdlet
Chapter 2
Stage Caves icon.pngStage Catacombs icon.pngStage Flooded Caves icon.png
FistulaChubC.H.A.D.Carrion QueenDark OneGurdyGurdy Jr.The HollowThe HuskMega FattyMega MawPeepPestilencePolycephalusThe WretchedThe FallenThe Headless Horseman
The ForsakenThe FrailThe Stain
Big HornRag Mega
Chapter 2.5
Stage Mines icon.pngStage Ashpit icon.png
Reap CreepTuff TwinsHornfelGreat GideonSingeThe ShellThe Pile
Chapter 3
Stage Depths icon.pngStage Necropolis icon.pngStage Dank Depths icon.png
The AdversaryThe BloatThe CageThe GateMonstro IIGishLokiMask of InfamyWarThe FallenThe Headless HorsemanMom
Sisters Vis
Reap CreepThe Pile
Chapter 3.5
Stage Mausoleum icon.pngStage Gehenna icon.png
The SirenThe HereticThe VisageThe Horny BoysMomMom's Heart
Chapter 4
Stage Womb icon.pngStage Utero icon.pngStage Scarred Womb icon.png
BlastocystThe BloatConquestDaddy Long LegsTriachnidDeathLokiiMama GurdyMr. FredScolexTeratomaThe FallenThe Headless HorsemanMom's HeartIt Lives
Sisters VisThe Matriarch
Stage Corpse icon.png
ChimeraThe ScourgeRotgutMother
Chapter 5
Stage Sheol icon.pngStage Cathedral icon.png
Chapter 6
Stage Dark Room icon.pngStage Chest icon.png
???The LambMega Satan
The Void
Stage The Void icon.png
Stage Home icon.png
DogmaThe BeastUltra DeathUltra FamineUltra PestilenceUltra War
Greed Mode
Ultra Greed
Ultra Greed
Ultra Greedier
The Binding of Isaac: Rebirth The Binding of Isaac: Rebirth The Binding of Isaac: Rebirth
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Characters Characters MainPageBabies.png Co-op Items Items Item pools Item pools Monsters Monsters Objects Objects
Pickups Pickups Pills Pills Rooms Rooms Seeds Seeds Transformations Transformations Trinkets Trinkets