The Binding of Isaac Wiki

Xxx form2 Isaac 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 is identical to normal Teratoma, but spawns 2 extra Spiders every time it splits.

When the final small Teratoma is destroyed, it spawns a Big Spider.


  • 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) (Don't google it if sensible)



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???