Over the years, Hollywood has pulled out all the stops when it comes to Halloween, giving us hundreds of spectacular looks to appreciate and imitate. Plenty of stars have gone the sexy route - we're looking at you, Kim Kardashian - while others opt for dialing down the sex appeal. And of course, we can always expect the industry's hottest couples to pair up and shut it down. But perhaps the most fun costumes have been those that dial up the horror, just enough to give you the creeps. We're talking zombies, skeletons, and yes, plenty of creepy clowns. Keep scrolling for some of the scariest celeb Halloween costumes.