Qetesh

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

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

History
The Qetesh imprisoned one of their species who took on the name Ruby White. They placed the prison craft into space, however Ruby managed to escape. She then travelled to many planets and drained them. (SJA: Goodbye, Sarah Jane Smith)