Costmato Fel-Fotch Hangle-Wang Slitheen, or simply Cosmo, was a member of the Slitheen family. He was a friend of the Tenth Doctor's until he accidentally got Cosmo's brother Hisk killed by a bull. He travelled to Earth with his Slitheen relatives to make money in 1500 B.C. Unfortunatley for Cosmo, the plan failed and he was arrested. (PROSE: The Slitheen Excursion)

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