Calufrax

Calufrax was an oblate spheroid planet, and the last world captured by Zanak and reduced to a trophy the size of a football. Its metricized structure, having a variable atomic weight, betrayed its origin as, not a natural planet, but the second segment of the Key to Time, and was recovered by the Doctor and Romana. The Doctor considered Calufrax to be dull, boring, and tedious. (DW: The Pirate Planet).


 * A possibly related planet, Callufrax Minor, was later stolen and taken to the Medusa Cascade (DW: The Stolen Earth).