The most terrible of all "Doctor Who" villains to ever carry a plunger. Though some of you have experienced more pain from a plumber's bill, the Daleks' plungers have earned their body count and push the buttons of The Doctor from calm to enraged. Their ability to keep from vanishing from the mythos showcases their ingenuity, popularity and all out danger as they live to both conquer and end The Doctor's life. Plus, their key phrase of "Exterminate!" is just far too fun to not yell out at the most inappropriate times.
Taking a fairly classic look for their outward appearance, the Silence lurks in the periphery until directly focused upon. The fear comes in the loss of memory when your focus changes and there you get an insidious "Doctor Who" villain. Imagine an enemy that you keep forgetting exists and you'll have a creature that freely walks among the population without any obstacles to whatever they wish to perpetrate. Forgetfulness becomes a psychological weapon that builds a truly great monster.
A rock that loves a bit of blood doesn't seem scary, but think of how many stones you've sat down on or played with and you'll realize you should've taken that geology class more seriously. Now take that to the next level and try to punch out a rock and you have a monster that is near invulnerable and wants to use you like a big Hi-C box but without the courtesy of a straw. You'll never look at Stonehenge the same way again once the Ogri get their shot at you.
The Weeping Angels
Taking the staring contest to the same level as Russian roulette, the Weeping Angels make their moves only when their victims blink. A greatly terrifying "Doctor Who" villain, the audience was only able to see the angels in their frozen repose between actions and that fed the creepiness factor. Knowing your death can only be staved off by some seriously dry sockets, you can feel the tension in the characters as they do their utmost to stay alive and escape all without breaking eye contact. Absolute proof that the things that go bump in the night can see you with your eyes closed.