The Blighted Ovum is the posthumous version of Gemini appearing in The Cellar and The Catacombs. He has a higher chance of appearing if Isaac has killed Gemini before.

The Blighted Ovum spawns already separated, similar to the green Champion version of Gemini.


The larger sibling appears as a mangled and bloody zombie, with parts of the skull eaten away. He leaves behind a trail of red creep as he moves, which damages Isaac for a full heart. Unlike Gemini, he will constantly pursue Isaac, not stopping for breath after charging.

Meanwhile, the other half appears as an invulnerable spirit, and is passive unless Isaac gets in his line of sight, in which case, he fires a blood beam similar to Brimstone. He tends to stay floating in the area it spawns in, not moving around much. 

Upon death, each half shoots radial blood shots, similar to when Steven is killed.

Champion Variants


Much like Eternal Gemini and Eternal Steven, Eternal Blighted Ovum starts with 1 large sibling and 2 small invulnerable ones. The large one acts exactly the same as its normal counterpart but he can slowly regenerate HP and is able to destroy rocks. The other 2 small ones fire blood beams at Isaac. All of them explodes into fast 8-way bullets on death.


  • If The High Priestess is used on the Blighted Ovum, Mom's foot will stomp on the smaller twin, doing no damage and thus being useless.


  • They appear in the Wrath of the Lamb DLC for the original game.
  • The Blighted Ovum no longer appears in the Catacombs since Rebirth.
  • In medicine, a blighted ovum is a pregnancy in which the early pregnancy appears normal on an ultrasound scan, but later no visible embryo develops. This likely refers to the smaller twin being dead (a spirit).
  • The large bite on the top of the head is on the opposite side on the artwork and sprite; this is probably unintentional.
  • He is also missing his jaw like Daddy Long Legs and Headless Horseman.

Regular Bosses
BlastocystChubDaddy Long LegsDark OneDingleDuke of FliesThe FallenFistulaGeminiGurdyGurdy Jr.GurglingsThe HauntLarry Jr.LokiMama GurdyMask of InfamyMega FattyMega MawMonstroMr. FredPeepPinPolycephalusScolexTurdlingsWidow

Afterbirth: BrownieDangleLittle HornRag ManTurdlings
Afterbirth †: Big HornRag Mega
Antibirth-only: Baby PlumBeelzeblubChimeraGreat GideonHornfelThe RainmakerReap CreepRotgutThe ScourgeThe SirenTuff TwinsWormwood

Posthumous Bosses
The AdversaryThe Blighted OvumThe BloatThe CageCarrion QueenThe GateThe HollowThe HuskLokiiMonstro IITeratomaThe Wretched

Afterbirth: The ForsakenThe FrailThe Stain
Antibirth-only: The HereticThe PileThe Visage

Alternative Bosses

Afterbirth †: Sisters Vis

ConquestWarFamineDeathPestilenceHeadless Horseman
Final Bosses
???IsaacIt LivesThe LambMega SatanMomMom's HeartSatan

Afterbirth: HushUltra Greed
Afterbirth †: Delirium
Antibirth-only: The Witness

Seven Deadly Sins
Seven Super Deadly Sins
Super EnvySuper GluttonySuper GreedSuper LustSuper PrideSuper SlothSuper WrathUltra Pride
Angels / Demons
KrampusGabrielUrielFallen Angels
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