Xxx form2Isaac Rebirth

Teratoma (テラトーマ Teratōma) is a boss added to the Wrath of the Lamb DLC. It resembles a posthumous version of Fistula.


It acts like Fistula, but spawns 3 medium sections instead of 4. Teratoma also spawns small Spiders when the smallest part of it is destroyed. It is a boss in The Womb I and Utero I . Total HP: 60 (large) + 3x15 (medium) + 6x8 (small) = 153

In The Binding of Isaac: Rebirth, any room layout in the Catacombs and Necropolis that should contain Fistulas in WotL now contain Teratomas.

  • Be careful to not split off too many parts at once. This could impair your ability to dodge.
  • Anything that damages multiple enemies will help you speed up the battle (especially when a larger amount of sections are present on the screen)

Champion Variant


Eternal Teratoma acts exactly the same as its original counterpart, but it shoots bullets on death.

When the initial large Teratoma is destroyed, it releases 4-way bullets.

When the second medium Teratoma is destroyed, it releases 6-way bullets.

When the final small Teratoma is destroyed, it releases 8-way bullets and spawns Spiders.


  • In biology, a teratoma is a tumor like growth that contains normal tissue from each of three germ layers (like hair, teeth or even bones). Like Fistula, these medical facts reference to their appearance (note the bones around Teratoma).



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
Community content is available under CC-BY-SA unless otherwise noted.