Judge (The Blood Cell)
The Judge was a mechanical creature found within an asteroidal Prison used by the "HomeWorld".
The original form of the Judge is unknown. By the time that it was found by the Doctor, it had grafted so much biomass onto its form that its original body could not be seen. Its form resembled a massive version of one of the Prison's robotic Custodians.
The Judge's motives are somewhat vague. It claims to have been sent (presumably by someone from the HomeWorld) to elliminate all prisoners within the Prison but once it was activated, it discovered that a plague was ravaging the HomeWorld. It then began experimenting on prisoners to discover if sin was the source of this infection. After experimenting with a prisoner, it would graft the corpse of the prisoner onto its own form. It was also able to attach still-living beings onto its body to serve essentially as voices for itself, though this proved fatal for the unlucky being chosen. (PROSE: The Blood Cell)