Mega Fatty (メガ・ファッティ Mega Fatti) is a boss appearing in The Caves from Chapter 2. As his name implies, he is a boss version of the Fatty enemy.

Description Description

Mega Fatty is a large, bloated humanoid with beady eyes streaming bloody tears. He has one tooth at the bottom of his blood-stained mouth. Furthermore, he has stubby arms.

Blast Behavior

Mega Fatty will not move or chase the player, unless jumping up and landing in the place where Issac is. (similar to Monstro's cycle of attack) The player must be wary, as his 'pooping' attacks are long range and also tracking. He is usually easy to kill after one or more encounters with him.

Mega Fatty has a number of different attacks:

  • Mega Fatty can hold, and fart, pooping out a dip. He may poop out more than one.
  • Mega Fatty can hold, and fart, also pooping out an array of "poop" bullets towards Isaac.
  • Mega Fatty jumps up, then lands in the position Issac is, leaving red creep around where he landed.
  • Mega Fatty opens his mouth, and then poops out an array of homing brown bullets towards Issac. The bullets will keep on shooting at Isaac for a while, then will stop.

Shield Champion Variants

Mega Fatty has two different champion variants.


Has 10% less health, Instead of leaving creep he shoots out 6 bullets when ever he farts he creates red poop but no dips and when he is about to vomit he dose it outward similar to a mom's heart attack.


Has 15% more health never vomits nor spawns dips but instead when he mega jumps he will fire out a shockwave similar to the cage.

Question Trivia

  • He has the highest amount of health out of all bosses from Chapter 2.
  • He may be based (or similar to) the mini-boss Gluttony, one of the seven deadly sins.
    • Oddly enough, during his death animation, Mega Fatty's face look eerily similar to Gluttony.
  • Early-Fatty

    An early sprite for Mega Fatty.

    From the game files when using the room editor, there is a boss sprite appearing to be the earlier version of Mega Fatty. (Relic-Rebirth?)
    • Curiously, this early sprite is identical to the final Mega Fatty's sprite for Isaac's Last Will.
The Binding of Isaac / Rebirth
Regular bosses Original: BlastocystChubDuke of FliesThe FallenFistulaGeminiGurdyLarry Jr.LokiMonstroPeepScolex
(Wrath of the Lamb: Daddy Long LegsGurdy Jr.Mask of InfamyPinWidow)

Rebirth: Dark OneDingleGurglingsThe HauntMama GurdyMega FattyMega MawMr. FredPolycephalus
(Afterbirth: BrownieDangleLittle HornRag ManTurdlings)
(Afterbirth †: Big HornRag Mega)

Posthumous Bosses Original: Monstro II
(Wrath of the Lamb: The Blighted OvumThe BloatCarrion QueenThe HollowThe HuskLokiiTeratomaThe Wretched)

Rebirth: The AdversaryThe CageThe Gate
(Afterbirth: The ForsakenThe FrailThe Stain)

Alternative Bosses Original: C.H.A.D.GishSteven
(Wrath of the Lamb: Triachnid)

Rebirth: Sisters Vis (Afterbirth †)

Harbingers Original: WarFamineDeathPestilenceHeadless Horseman

(Wrath of the Lamb: Conquest)

Final Bosses Original: It LivesMomMom's HeartSatan
(Wrath of the Lamb: ???Isaac)

Rebirth: The LambMega Satan
(Afterbirth: HushUltra Greed)
(Afterbirth †: Delirium)

Seven Deadly Sins EnvyGluttonyGreedLustPrideSlothWrath
Seven Super Deadly Sins Super EnvySuper GluttonySuper GreedSuper LustSuper PrideSuper SlothSuper WrathUltra Pride
Angels / Demons Original: Krampus

Rebirth: GabrielUrielFallen Angels

The Legend of Bum-bo
Regular bosses BygoneDuskGibsGizzardaLoafPeeperPyreSangreShy GalThe Duke
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