Amelia Hubble was a Cion, and the last of her kind.
Landing on Earth in 2012, she went to Hollywood, where she fed on the creative plasma energy of people in the film and television industries. This caused production and activity in the city to diminish drastically. When the Tenth Doctor and Donna Noble found her, she attacked the Doctor, but Donna was able to stop the plasma exchange.
Amelia escaped, but they tracked her to the home of director Alan Crawford and prevented her from feeding on him. The Doctor told her he could build a device which would allow her to obtain the energy she needed from the Internet. She agreed, and when the Doctor and Donna returned to Hollywood a year later, everything was back to normal.