Mega Fatty

Mega Fatty is a boss that can appear:

Only in the Caves.
In the Caves and the Flooded Caves.

Behavior

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:
- Summon 1-3 Dips.
- Unleash a cluster of either small or big projectiles behind him, similar to Monstro.

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 projectile 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.

Gallery

Brown Champion Mega Fatty.
Red Champion Mega Fatty.
Mega Fatty as one of Delirium's forms.
An unused sprite for Mega Fatty found among the Room Editor icons.
Concept art for Mega Fatty on the top middle and top right, along with other Rebirth boss concept arts.

Notes

Lost Contact will still block all incoming projectiles from his barrage, even if they happen to go high enough to be offscreen.

Trivia

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.