- Additionally in the Flooded Caves.
- Leaps off-screen and tries to land on Isaac's position, leaving a large puddle of Red Creep upon landing.
- Slides briefly towards Isaac and performs a short-range jump, also leaving Red Creep when he lands.
- Inhales, drawing in Isaac and any monsters towards him, before then vomiting upwards, unleashing a barrage of projectiles into the air. The projectiles will rain down for a short duration, following Isaac's movements.
- Farts, which can damage Isaac if he's too close, and will either:
Champion Versions 
- Brown: Has 15% more HP (690). He will not use his vomit attack and sends out rock waves instead of leaving Red Creep upon landing when performing the long-range jump, similar to The Cage.
- Red: 33% smaller and has 10% less HP (540). Shoots 6 bullets instead of leaving Red Creep upon landing. Creates Red Poop instead of Dips. Vomit attack sends out four projectiles stream attacks in a pattern similar to Mom's Heart/It Lives. Due to the high tear height of the vomit attack projectiles, it is nearly impossible to get hit by them.
Mega Fatty as one of Delirium's forms.
- Lost Contact will still block all incoming projectiles from his barrage even if they happen to go high enough to be offscreen.
- He is the boss version of the Fatties.
- The Cage is the posthumous version of Mega Fatty.
- The picture of Mega Fatty on Isaac's last will closely resembles the unused variant.
|The Binding of Isaac: Rebirth|
|Achievements||Attributes||Bosses||Cards and Runes||Challenges||Chapters|