A few months ago my wife and I watched a movie about a time-traveling law enforcer who was chasing an elusive time-hopping bomber through time. At the conclusion of the film, our time-traveling hero finally came face-to-face with his nemesis.
In a mind-bending paradox, he found that his enemy was actually his future self. As his twisted future self arrogantly pontificated about how he had become what he was, the "present" self adamantly rejected the notion and declared he'd never become what he saw before him. He then shot and killed his future self.
He became the instrument of his own demise.
Full story from the WindowsCentral blog...