Doctor Who: 10 Best NuWho Villains That Only Appeared Once

6. Prisoner Zero

Episode: The Eleventh Hour The Eleventh Hour is rightly regarded as one of the best post regeneration stories in all fifty years of Doctor Who. It gave us everything we could have wanted, a brilliant new Doctor, a brilliant new companion, fish custard, arguably the most unique companion introduction ever, the start of a great series arc, oh and a giant shape-shifting viperfish. But the beginning of Matt Smith's tenancy in the TARDIS could have been vastly different without his very first villain. Prisoner Zero gave the Eleventh Doctor a challenge, to prove that he could step into the sandshoes of his predecessor. This episode and its villain shaped the future of Doctor Who, as it headed into a (insert opinion here) new era. The best thing about Prisoner Zero is the contrasts between his true form, and those he takes on. Each is different, yet somehow they never lose their sense of menace. Even during the hospital scenes, where Prisoner Zero takes on the form of a Mother and her two daughters, you never lose the sense that something is very wrong with them. At first you would think that the overuse of Prisoner Zeros human forms would weaken the character, but by the episodes final showdown these perceived weaknesses have been turned into strengths. And we are treated to a villain that's great in all forms. One last thing, a scene was originally written by Steven Moffat, in which it was explained why Prisoner Zero was in jail in the first place. Although this didn't make the final cut, it went something along the lines of Prisoner Zero taking over an entire planet by impersonating an entire army. That's pretty damn cool.