Dat Tex Fine Slitheen was a male member of the Slitheen family, married to Bioo Goo Von Bar. He posed as Jay Stafford and attempted to avenge his family after their defeat by Sarah Jane Smith. He ended up forming an alliance with her, Alan Jackson and Mariah Jackson, after the Xylok, "Mr Smith" tricked them into aiding him in his plans. Whilst breaking into their house, the Jackson's discovered Jay Stafford's body hung up, like a piece of clothing. After revealing this to Sarah Jane, they set off to stop the three Slitheen. After discovering the true motives of the evil Xylok's motives, Dat and Bioo decided to help. Ultimately, Mr Smith's plan was foiled, and the three Slitheen left the planet.