Small bladdery and bloody clump of tissue.
This repugnant organism can on occations be seen floating in the river Phlegethon.
There it is feeds on the rotten and dissolved bodies of those who have met their demise on the banks of that vile flux of doom.
Ultimately the floating cocoons burst open, giving birth to the very creatures you have been slaying in these mazes.

Spirit tech must be one grizly business...