A prison planet was a planet used by a species, group or organisation as a prison. Some prison planets resembled prisons such as the Stormcage Containment Facility and Volag-Noc. (DW: The Infinite Quest, The Pandorica Opens) Others included the planet Dis, used by the Imperial Landsknechte during the rule of the Earth Empire as a prison due to its proximity to a sun. (NA: Original Sin) Other planets were chosen as prison planets to serve dual roles as a prison environment and sourcing a rare or useful material: New Rarga, where wompom was grown and harvested, and Raaga, a world rich in Tinclavic. (BNA: Ghost Devices, DW: The Visitation)