Secret Window (2004)

Ending spoilers. The accusing stranger is Mort's own creation, and Mort is responsible for the violence. There is a useful idea here about a writer editing himself into the victim of his own story. The difficulty is that the reveal leans on a familiar split-identity mechanism, then spends energy rearranging appearances. Johnny Depp's slouching, resentful performance gives the character more unsettling specificity than the explanation alone.