Qetesh

The Qetesh were a species that fed off excitement in people's lives, draining their life essence with it. They were masters of emotional manipulation and were also known as "soul-stealers". (TV: Goodbye, Sarah Jane Smith)

Biology
The Qetesh outwardly resembled humans, though they possessed far greater strength. Their stomachs existed outside their bodies. They did not need air to breathe. (TV: Goodbye, Sarah Jane Smith)

History
The Qetesh imprisoned a member of their species, who took on the name Ruby White. When they placed the prison craft into space, Ruby escaped. She travelled to many planets, and drained them. She was recaptured by Sarah Jane Smith after the journalist defeated her, with help from her beloved team. (TV: Goodbye, Sarah Jane Smith)