Simon Cowell: The TV talent judge is less afraid of bad pitch than he is the number 13 -- a phobia known as triskaidekaphobia. In an Skype interview with fans, he said he doesn't even like the number 67, because 6 + 7 equals the magic number.
Fear of clowns, spiders, enclosed spaces -- not uncommon. But fear of submarines and butterflies? A little weird. Take a look at what keeps these celebs up at night.