In K-PAX, Kevin Spacey plays Prot, a man who claims to be an alien visitor from the titular planet. Unsurprisingly, he's quickly directed towards a mental institute, where psychiatrist Mark Powell (Bridges) tries to assess his condition.
The central conceit is certainly intriguing, but it does eventually become a bit trying, much like Spacey's smug performance.
Laidback Dude? He gets a bit unsettled when Prot exhibits some convincingly alien characteristics.