Dax Fex Fize Slitheen

Dat Tex Fine Slitheen is a male member of the Slitheen family, married to Bioo Goo Von Bar. He posed as Jay Stafford and attempted to destroy Sarah Jane Smith and avenge his family. He ended up forming an alliance with her, as he had been double-crossed by a Xylok. He eventually left, no harm done, apart from the man he killed. (SJA: The Lost Boy)