The Bloat can be an extremely difficult boss for beginners because of its behaviors. Its behaviors are as follows:
- The Bloat's eyes bounce around the room, dealing contact damage to Isaac and blocking tears.
- When Isaac is in front of The Bloat, it will shoot Brimstone lasers from each of its eyes to the South.
- When Isaac is beside The Bloat, it will shoot Brimstone lasers from each of its eyes to the East and West.
- The Bloat will spawn Creep on the ground.
- The Bloat will jump towards Isaac, spawning Creep and shooting tears in many directions on contact.
The Bloat will randomly spawn as a Champion variant. This variant will be Green and, instead of shooting normal tears, it will shoot two IPECAC (explosive) tears.