It's no surprise at all that evil twins have made an emergence in The Vampire Diaries, TV's most simultaneously clichéd and yet watch-able vampire-laden series yet. Following in the footsteps laid by Joss Whedon more than 10 years before, the sudsy Vampire Diaries has introduced an evil vampire twin version of Elena into the mix, Katherine. Again, the main difference really is the outfit. Oh, and that Katherine is one of the undead. As we've seen from Willow's evil twin, vamps love to dress all bad-ass and stuff, and Katherine uses this to full effect to demonstrate her vampness. What I'm getting from all this is that if you ever come across your evil vampire twin, she's probably going to be a hell of a lot more sexy, confident and bad ass than you are. Unless you're a guy. In which case, your evil twin will probably just have a beard. Katherine is memorable for demonstrating to us that Elena could be far less of a wet blanket than she is - if only she allowed herself to become a creature of the night.
6. Battlestar Galactica
Battlestar Galactica is a fantastic show, and is one that took the evil twin twist and decided to make this the basic concept of the series. Each humanoid Cylon character is simply one of many, and this is best demonstrated when Boomer, a loyal soldier of Galactica finds out not only that she has a whole cohort of evil twins wearing the same skin as her, she is actually a Cylon herself. Creepy. Her main 'evil twin' through the show is Athena, who happens to be the same cylon model as Boomer. While most shows use the evil twin concept as a plot that can usually be wrapped up in one or two episodes, we actually get to see some character development between Athena and Boomer. At the beginning of the series we are suspicious of Athena and see her as the malignant twin - but by the end of the series, we're not so sure. Athena and Boomer are memorable for the complexity of their character development but also the crucial importance of their story arc to the series as a whole.
5. Doctor Who
Back in the days when the Doctor wasn't embodied by a hipster sporting bow ties and instead was portrayed by the very-British Tom Baker, the Doctor ran into trouble on the planet Tigella and ended up acquiring a body double. Meglos is a shape shifting cactus creature with a penchant for mimicking the Doctor's form (they say imitation is the sincerest form of flattery, after all). Unusually, this evil twin was easy to spot not because of a beard, or a bit of a scowl, but because he was covered in cactus spines. Subtle. It didn't take long for Meglos to reach his demise at the hands of his Timelord twin but it was fun while it lasted. Meglos makes it onto our list of memorable twins for being probably the least subtle of evil twins.
