Planet (Head Games)

A planet home to a tribe of savages was where Jason created the Galactic Prison to house the Seventh Doctor and his "accomplices," although ultimately only the Doctor and Mel Bush were left there.

Having taken control of the Doctor's TARDIS with Dr. Who, Jason left them in the Prison composed of fictional energy sustained by his mind as long as he thought about it, along with dinosaurs to guard the Prison, where the dinosaurs attacked some of the savages. (PROSE: Head Games)