Doctor Who: 10 Scariest Episodes That Sent Us All Behind The Sofa

9. The Impossible Planet/The Satan Pit

It's perhaps a surprise that he didn't make an appearance in a Doctor Who finale, as the Beast wasn't just one of the most fearsome villains during the reign of Russell T Davies. He was the perfect equal to David Tennant's Doctor; a lonely demi-deity, feared by so many, ancient and the last of its kind. That alone would have been a fascinating premise for an episode, but 'The Impossible Planet' two-parter proved to be more than just a story hinging on a mythical creature. We only see the Beast towards the very end of the hour-and-a-half running time, but we see him possess Toby, tell him "Don't turn around" with bassy depth, and we see him take over the collective mind of the Ood, the gentle slave race of the crew. The language of the Beast is so old not even the TARDIS can translate it, and the creature is suggested to be behind the idea of Satan. It's mysterious, horribly dark and no one's safe: most of the crew die in the end. Series 2 looked deeper at the relationship between Rose and the Doctor, with the moments of darkness coming few and far between. This was a welcome surprise amidst the more soapy storylines; it chilled its audience to the bone, and brought the Doctor even closer to his companion.