Slitheen

The Slitheen are a fictional family featured in the British science fiction television series Doctor Who. They first appeared in the ninth episode of the first season of the Doctor Who revival series, "Aliens of London".

Overview
The Slitheen are a family of extraterrestrials from the Raxacoricofallapatorian race. One of their most notable members, Blon Fel-Fotch Passameer-Day Slitheen, came to Earth in 2005 and killed MI5 agent Margaret Blaine. She crafted a skin suit in her likeness and took her place, using the human Blaine's connections to make a go at becoming the mayor of Cardiff, Wales.