Children (The Eleventh Hour)
From Tardis Wiki, the free Doctor Who reference
Two children, daughters of a woman who was in a coma in the Royal Leadworth Hospital in 2008, appeared when Prisoner Zero used their mother's body to trick Amy Pond and Rory Williams into thinking they were hospital patients. The disguise soon failed when Amy noticed that one of the children started to speak using her mother's voice. (TV: The Eleventh Hour)
