7. The Machinist
In this 2004 Brad Anderson film, a pre-Batman, anorexic and sleepy Christian Bale portrays the insomniac Trevor Reznik battling with reality, to control his body and mind as well as battling the recurrent figure of Ivan. The plot mainly surrounds Trevor's increasingly alienated relationship with the outside world, his co-workers, and his love interests, Stevie and Maria.
The Reveal: Protaganist figure Ivan is revealed to be nothing but a figment of Trevor's sleep-deprived and twisted mind, which causes as much shock as a large frothy glass of Beer in a Bavarian beer house. As soon as Ivan appears early on in the Film as a shady figure in the industrial environment, who only Trevor interacts with and even cannot be found in the company's employment files, it takes little time for the audience to begin to whisper 'it's all in his head' to each other.