Actresses Tara Reid and Cassie Scerbo thought the director of their monster movie was playing a joke on them when he told them he was changing the title to Sharknado. The film, about a freak storm which scoops up man-eating sharks in tornadoes and deposits them in cities, became an unlikely phenomenon after it aired on TV in America on Thursday (11Jul13), taking Twitter by storm and earning a legion of fans. However, Bring It On star Scerbo has revealed the film was originally called Dark Skies, but had be changed after a horror movie of the same name hit cinemas in February (13), and she thought director Anthony C. Ferrante was joking when he told them the new title. She tells The Hollywood Reporter, "When our director Anthony Ferrante came on set and was like, 'Guys, we think we have to change the title. We're thinking about Sharknado.' We actually thought it was a joke. We were like, 'Haha, that's funny.' "He was like, 'No, I'm serious.' We were dying. 'There's no way!'... "We were like, 'This is ridiculous and embarrassing.' He was like, 'Just you wait, this name will actually do so much for the project.' We were like, 'All right, whatever!'" Scerbo admits she was stunned by the film's instant success, adding, "It's trending (on Twitter) for more than 24 hours. I can't even believe it... I'm completely stunned and blown away. This funny little film we did called Sharknado has caused so much buzz, I would have never imagined. It's literally caused more buzz than anything else I've ever done. I had no idea that it was going to turn into this phenomenon."