Teratoma is the posthumous version of Fistula.
Teratoma's only attack is to move around the room, changing directions when it bumps into walls. When the original Teratoma is defeated, three smaller Teratomas will be spawned. Defeating each smaller Teratoma will spawn two smaller Teratomas. After the smallest Teratomas are defeated, they will spawn two spiders, unless they are defeated over an obstacle or pit.
- A teratoma is a tumor that contains tissues which are atypical for its placement in the body. It can include hair, teeth, bones and so on.