While Doctor Who does body horror particularly well, as evidenced by how many examples of it there are on this list, it also excels at psychological horror, especially in the 2005 series. One of the best examples of this is the story Midnight, in which some sort of alien creature takes over the mind of a passenger on a caravan the Doctor is on and begins slowly but surely turning all of the passengers against him - before taking control of him itself. Not only is it genuinely creepy to have a creature that forces you to repeat whatever anyone says to you, it's ten times worse that the most powerful and clever man in the room is also the most vulnerable to it, leaving the salvation of everyone to a nameless stewardess. Leslie Sharp and David Tennant's performances both sell the terror in this story particularly well, but the basic concept alone makes it one of the most scary stories the new series has ever done. (And yes, we're not forgetting that other time the Tenth Doctor got possessed, by the sun creature in 47, and how scary Tennant was in that. Or how scary Tennant as the Tenth Doctor is in general. At times, he makes Capaldi look downright cuddly.)