While others prepare for Christmas and advent calendars, we're getting ready for the best holiday of the season … Halloween! Okay, it might only be the only time we can get festive during autumn but it's prime time to get your decorations up and throw a spectacularly spooky (or sexy) party. And this year, we're after trio Halloween costume ideas. Solo Halloween costumes will always go down a treat, but this Halloween, why not try something with two of your closest pals? That's right, trio costumes are the best way to dress collectively, showcasing your undying friendship, but to also ensure all attention is on you and your friends. There's no doubt you'll win best dressed if you opt for something classically scary or cosplay as your favourite TV characters, like The Plastics from Mean Girl...