4. The Slitheen - Aliens Of London/World War Three (2005)
Any fan of Nu-Who can guess what my problem with the Slitheen is right away. Although the design leaves a fair bit to be desired, it's passable. Their plan (to destroy the Earth and sell it) is relatively original for Doctor Who and realised pretty well. I can even get past the zipper in the head thing. But the truly terrible thing about the Slitheen that stops them being anywhere near frightening or impressive is the farting. They fart. They're farting aliens. That's their unique selling point. To hell with the creative elements of other monsters like the Sontarans and the Cybermen. What these aliens really need is chronic wind. The worst thing though is that as well as it being lowbrow humour (Which is milked for all it's worth), the farting is a plot point as it's a sign that a person might be a Slitheen in disguise and the smell of their farts helps the Doctor to identify that their bodies are made of calcium. I know Doctor Who is a family drama and it shouldn't always be taken seriously but really? Farts being used as vital plot element? Thankfully the Slitheen have only returned to Doctor Who once and their return went some way to being a saving grace for them with less bad comedy and a slightly darker tone. Let's hope they don't return for a while if ever.