every episode, Jailbot is tasked with capturing and torturing a criminal named Jackknife and bringing him to Superjail, often maiming or killing innocent bystanders in the process. A running gag for the intro in the first three seasons shows Jailbot carrying Jacknife through various other dimensions into a cloud resembling Warden's head which leads to Superjail. In the episode "Jailbot 2.0", the Warden claims that Jailbot single-handedly built the vast prison, but flashbacks suggest that Jailbot is really the latest in a series of similar robots. He's mute, with a dot matrix screen that displays a simple expressive face. Despite his ruthlessness, Jailbot also possesses a childlike personality, protecting the Warden from any harm and watching out for the welfare of young children who come across his path, however, he can be cold and ruthless to children who are mean to him; Christy Karacas described him as a "red-headed stepchild...seeking approval." He has even shown compassion for Jacknife, such as releasing him in "Best Friends Forever". The Doctor (voiced by Christopher McCulloch) – The resident physician of Superjail. He regularly experiments on the inmates in grotesque ways and has a German accent, but at times says words in French. It was revealed in "Vacation" that he fought in World War II and was at one point a POW. The Twins (voiced by Richard Mather) – Two green-blooded, blonde, identical twin aliens with European-sounding accents who inhabit a laboratory underneath Superjail and wear outfits resembling those worn by the Sandmen in Logan's Run. They took a year abroad trip to Earth and then decided to stay much to their father's chagrin. Their on-screen appearances are accompanied by techno music. The Twins use their alien powers—including teleportation, shrinking, and materializing various items to interfere with the Warden's plans for their amusement. Although their plots often result in mass death and destruction, the Twins do not appear to harbour any malice towards either the Warden or the prisoners. Jackknife (voiced by Christy Karacas) – A low-level criminal who appears in the openings of most episodes committing crimes before getting captured and brutally tortured by Jailbot, where his subsequent journey through various "outer worlds" and back to Superjail makes up the opening credits sequence (with the latter being omitted in the 4th and final season). He's often depicted escaping the jail during the murder sequences in the first season and periodically throughout seasons 2