The Binding of Isaac Wiki

The art cover showcasing Isaac being surrounded by several bosses.

Bosses are much stronger monsters and must be fought at the end of each floor. The boss will be randomly chosen based on which area the player is currently in. Some bosses can be Champions like normal enemies, which can change their pattern somewhat; this occurs more often once the player has beaten the full game for the sixth time and onward.

Upon death, bosses either drop an item which increases a single stat or an item unique to that particular boss. In addition, they drop random health pickups; two at the start or one after unlocking "Everything is Terrible!!!". If the boss was an alternative version, it drops one additional random health pickup upon death.

Standard Bosses[]

Chapter 1[]

The Basement[]

The Cellar[]

(Wrath of the Lamb expansion)

Chapter 2[]

The Caves[]

The Catacombs[]

(Wrath of the Lamb expansion)

Chapter 3[]

The Depths[]


(Wrath of the Lamb expansion)

Chapter 4[]

The Womb[]

(Unlocked after defeating Mom)


(Wrath of the Lamb expansion)


Added in the Halloween update, can be entered by entering the trapdoor in the Devil Room after the Mom's Heart/It Lives! fight. After Ending 10, a trapdoor to Sheol will always appear after killing It Lives.


Added in Wrath of the Lamb, can be entered after killing It Lives! by touching the beam of light.

The Chest[]

After defeating Isaac while holding The Polaroid trinket, opening the golden chest in the middle will take you to The Chest instead of displaying ending 12.


(Except for floors where "final bosses" appear.)

Devil Room[]

Unlockable Bosses[]



These bosses are only available after defeating Mom for the first time, where after the credits you will unlock the secret "The Horsemen are on the loose!". They drop a meat cube upon defeat, and the player can fight one of them at the end of a floor by using the Book Of Revelations. Without it, it is extremely rare to fight enough Horsemen to finish a Meat Boy, although this is possible.

Alternative Bosses[]

These bosses are only available after finding their respective unlocks.


Each level has a chance to include a Special Room where the player can face a mini-boss.

The Seven Deadly Sins[]


The Seven Deadly Sins as seen in the credits.

The Seven Super Deadly Sins[]


The "Super Deadly Sins" were added in the Wrath of the Lamb expansion and will sometimes appear instead of the regular version of the accordant Deadly Sin.

Ultra Pride[]

The boss called Ultra Pride was added into the Wrath of the Lamb expansion in version 1.3. Upon defeating him, the achievement and item The Left Hand is unlocked.

Boss Treasures[]

Boss Drops

Common Drops
Wrath of the Lamb additions
Boss Specific Drops


  • If you have extra lives, either from collecting a 1UP, Ankh, or Dead Cat, bosses can be re-fought at the cost of one life in order to collect more items by killing oneself inside of their room - for example, with bombs or with the IV Bag. This can be abused to quickly gain all of the possible Boss Room upgrades and, with the aid of The Dice, can force normal Treasure Room items to spawn in the Boss Room by exhausting the Boss Room Item Pool. This can also be done with any of the Horsemen (who will drop one Cube Of Meat every time) and The Fallen (who will drop one Devil Room item every time). Gish will drop Little Gish every time, but every Little Gish after the first will act as Brother Bobby; the same is true of Little Steves dropped by Steven once Steven (item) is collected. Every Little C.H.A.D. dropped by C.H.A.D. after the first will not do anything. 
  • Similarly, spawning a Fly in the Boss Room with a Slot Machine (whether by using the Portable Slot Machine or a Tarot Card) will also result in a new boss spawning and a new item being dropped. This is likely because in rooms with Eternal Flies and Corny Poop, the regular flies left over will convert to nothingness and regular Poop, respectively, effectively causing a "reroll" of the room. This is also probably why flies reroll the Arcade to have a Fortune Teller when there's a fly in them.



The angry Boss face as it appears in Isaac (left) and The C Word (right).

  • The Health Bar at the top of the screen for each boss (excluding Mask of Infamy) has an angry face to the left of it. This is a reference to the Newgrounds site, where a character called Mr. Angry Face is known for that symbol.
  • Originally, every boss/enemy in The Binding Of Isaac was going to resemble Isaac in some way. This is the case for most. 3
    • Bosses in the final version, however, seem to be mutated animals/insects, such as Chub and Larry Jr.. How they became this way is unknown.
    • This original desire may be the reason Isaac (boss) exists.
Standard Bosses Dukeofflies fullThe Duke of FliesGemini fullGemini260x185-400px-Monstro.svgMonstroLarryjr fullLarry Jr.FistulaFistulaGurdy fullGurdyPeep FullPeepChubChubLoki fullLokiScolex fullScolexBlastocyst fullBlastocystTheFallen FullThe Fallen

Wrath of the Lamb DLC: 260x200-400px-Widow3WidowPin cleanPinMask of InfamyMask of InfamyGurdjrGurdy Jr.VS DaddyLonglegsDaddy Long Legs

Posthumous Bosses 285x230-MonstroII fullMonstro II

Wrath of the Lamb DLC: The HuskThe Husk260x220-The Hollow2The Hollow250x200-Teratoma.TeratomaLokii cutoutLokiiBlighted ovumBlighted OvumCarrionqueenThe Carrion QueenThe WretchedThe WretchedBc BloatThe Bloat

Alternate Bosses 287x265-Steven FullsizeStevenChub fullC.H.A.D.Gish fullGish

Wrath of the Lamb DLC: 200x300-400px-Triachnid boss portraitTriachnid

Harbingers 220x287-Isaac Vs famine edited- noobletkFamineBC PestilencePestilenceBC WarWarVSDeathDeath230x200-Headless HorsemanHeadless Horseman

Wrath of the Lamb DLC: BC ConquestConquest

Final Bosses 250x250-400px-MomMomMoms Heart FullMom's Heart250x250-ITLIVEScutoutIt LivesSatan FullSatan

Wrath of the Lamb DLC: Bc isaacIsaacBC xxx???