5. Sean Young
Sean Young's so insane that she spends most of her time these days making viral videos claiming that she isn't. Though she showed grand promise as the beautiful replicant Rachael in Blade Runner, her reputation as a loon began when, after losing her role as Vicki Vale in Batman (due to a horse-riding injury), she performed a speculative audition, hassling Michael Keaton and Tim Burton on the Warner Bros. lot to try and win the role of Catwoman (which eventually went to Michelle Pfeiffer), and even stitching a makeshift outfit for it. But that's not all; she's been kicked out of several awards shows, either for heckling winners or by turning up uninvited. Oh, and she stole her wardrobe from the set of Wall Street after being upset that she didn't get the meatier part played by Daryl Hannah. Oh, and James Woods claims that following the breakdown of their relationship, she stalked him. Oh, and she's an alcoholic, too.