Kalamity (movie, 2010)

Haunted by memories of his ex-girlfriend Alice, a heartbroken Billy returns home to Northern Virginia seeking solace from old friends. But what he finds there is more disconcerting: his best friend Stanley has become unstable, mysterious and withdrawn from those around him. Billy teams up with another old friend to find out what's going on and as they probe Stanley's recent activities, their friend's behaviour seems more and more bizarre and frightening.