Parasite Cells were going to be small red stationary cells that would consume all of your mass if you didn't get kill it in time.
These entities were developed and coded by Zeach, but never released to the public.
Parasite Cell and it's first victim.
Up to eight parasite cells can be on one server. They were going to be idle, but if you touched them, they would stick to you and start consuming your mass.
You had to splitkill one to get rid of it. After eating them, you will split in 16 pieces.