MutaNemos in Desert.
Creatures that look similar to real-life anglerfish, they are capable of running toward player in swarms and biting hard.
In the Lab level, sewer part, they cannot be killed. Instead the player must bunny-hop away from them, until they find a ladder that is guarded by a Panzerdemon. Only by killing this Panzerdemon they can destroy the MutaNemos that were chasing them, eventually ending the whole level.
In the Nuclear Plant, they will appear in the Sewers in an infinite amount until you teleport away from the Sewers. They will appear as soon as you get enough away from the entrance and activate the radioactive waste cloud. These versions are not counted in the monsters counter with the exception of their souls which lets us exceed the maximum. Also, they will drop green souls on death.
- The action which spawns the infinite amount of MutaNemos is called "Bugging".
- The "Bugging" action can be avoided by climbing the pipes on the wall and jumping at a certain point, but the MutaNemos which spawn along the way are still functional, unless you do the same method as well.