Monstro

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

Behavior

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.

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.

In the boss room, Monstro can be paired with Flies, Attack Flies, Gapers, Hoppers, Frowning Gapers, Mulligans, Cyclopias, or Ministros.
When Monstro jumps off-screen, he is cured of all status effects.
Monstro can't hop over Obstacles.
Larger Tears that Monstro shoots deal 1 Heart of damage, while the smaller Tears only deal half a Heart of damage.
- 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.
Monstro can rarely spawn in a room with two Blood Donation Machines.

Monstro appeared in the original The Binding of Isaac.
He is the boss version of the Ministros.
Monstro appears to be missing a tooth which appears as the item, Monstro's Tooth.
- Monstro also has a cleft lip.
Monstro is Monster in Portuguese.
- "Monstro" is a somewhat common mispronunciation of the Spanish word monstruo.
- Monstro is also the name of The Terrible Dogfish, a fish with a large mouth and many teeth from the book The Adventures of Pinocchio.