Doctor Who: 10 Worst NuWho Villains

10. The Krillitanes (School Reunion)

Like a couple of the other entries on this list, the Krillitanes are a weak villain in an otherwise solid episode.

There's lots to love about Series 2's School Reunion, whether it's the friction (and later, the banter) between Sarah Jane Smith and Rose Tyler, Anthony Head's delightfully unsettling performance as Mr. Finch, and even a supporting role for K9. But the Krillitanes just don't hit the mark whatsoever.

The basic idea behind these alien beasties is an intriguing one - they're capable of cherry-picking abilities and physical traits from other species, meaning they can evolve their forms in any way they like. Sounds good on paper, but in the episode, they're just... bats. They look like bats, fly like bats, and even hang upside down like bats.

For a villain that could, in theory, design itself to be as efficient and deadly as possible - while also stealing a host of badass abilities for itself - it's insane to think that this is the best portrayal that writer Toby Whithouse could come up with. Overgrown bats!

It makes for a dull interpretation of a villain that had so much potential, and it doesn't help that they look extremely similar to the Reapers from Series 1, meaning that the Krillitanes feel like a bit of a knock-off in comparison.