5. The Beast The Impossible Planet/The Satan Pit (2006)
This has arguably been Doctor Whos most daring monster yet. Doctor Who has mainly kept its distance from mainstream religion (though it did play a role in The Curse Of Fenric in 1989) until 2006 when we saw the Doctor come face to face with Satan himself. If you make the Devil the villain of a Doctor Who story, then youre really going to have to pull something special out of the bag. And writer Matt Jones did just that. The Beast is a simply a magnificent b*****d. Until his final defeat at the hands of Rose, hes always one step ahead of our heroes and is a master at manipulating those around him, especially the subservient Ood. A great part of the character is that his mere existence causes people to question their beliefs, even the Doctor. But his best moment comes when he comprehensively tears into each character, reminding them of their flaws such as security guard Mr Jefferson being haunted by the death of his wife and archaeologist Toby Zed's shame about being a virgin. As well as the Beasts characterisation, the CGI used for its physical body still holds up incredibly well after seven years, and Gabriel Woolf and Silas Carsons vocal performances add a brilliant extra dimension to the character. Even though hes been beaten once, the Beast still has the potential to all but crush the Doctor. After all, hes a complete genius whos several storeys tall and breathes fire. When youre dealing with that kind of villain, its entirely plausible that he could survive being sucked into a black hole as the Beast was.