Doctor Who: 10 Villains The Doctor Couldn't Defeat

10. Skaldak (Cold War)

The Eleventh Doctor episode Cold War finds the Doctor and Clara trapped onboard a submarine that is under attack by Skaldak, a member of the mighty Ice Warrior race.

With the Doctor being trapped in such a confined space with very few resources - and no TARDIS - there really isn't much he can do to stop Skaldak's assault, and as a result, the alien runs rampant, killing several crew members and threatening to unleash nuclear warheads upon the Earth, potentially killing billions.

This leaves the Doctor with one option: blow up the submarine, an act that would destroy the missiles and Skaldak, yes, but would also kill himself, Clara, and all the other innocent crew members onboard the vessel.

Fortunately, the Doctor doesn't have to do this in the end, but only because Skaldak leaves, and as an added bonus, he also decides to show mercy by not firing the warheads. If he had wanted to though, Skaldak could've easily blown the Earth to bits, and the Doctor would've been powerless to stop him.

The story ends with the good guys surviving and the Earth being left unharmed, but not because the Doctor beat the villain. If you boil it down, the Doctor actually lost this one, and things only turned out well because Skaldak chose peace instead of destruction.