| Floors of
| Base Health||250|
|Items Dropped||Boss Pool|
Monstro is an enemy in The Binding of Isaac: Rebirth that is present as both a Boss on The Basement floor and as a Monster in Boss Challenge Rooms, during Boss Rush, and on later floors.
Monstro spawns in the center of the room, sometimes having two Mulligans on his left and right. Monstro's attacks are as follows:
- Monstro can hop small distances towards Isaac in the player's vision, dealing contact damage.
- Monstro can jump large distances to Isaac's location when the jump was initiated in which it jumps out of the player's vision (above the screen) and lands, dealing contact damage and showering Isaac with a barrage of tears- large ones dealing one whole heart of damage, small ones dealing one half heart of damage.
- Monstro can vomit a barrage of varying tears from its mouth in one burst. As with his bigger jump, large tears deal one whole heart of damage and small tears deal one half heart of damage.
Monstro has a chance to be one of two champion variants:
- Monstro's dark grey champion variant is larger than the original and tends to both shoot more and jump less than the original
- Monstro's pink/light red champion variant is smaller than the original and generally spawns in pairs.
- Monstro has a cleft lip, this possibly being it's most defining feature.
- Monstro is missing one tooth, this tooth being an active item.
- Monstro's Lung is a Passive Collectible based off of Monstro, it giving Isaac the appearance of Monstro and a similar way of shooting tears.
- Both Monstro's appearance and bouncing behavior are very similar to that of the SnackOlantern from Edmund McMillen's game SnackOlantern.