For years, fans of The Big Lebowski (which is, obviously, everyone) have discussed and debated the possibility that Donny—the hapless bowler played by Steve Buscemi—is just a figment of Walter's Vietnam War-addled brain. John Goodman plays Walter as a pretty disturbed and haunted man, after all, and he interacts with Donny far more than The Dude (Jeff Bridges) does, leading people to think that Donny is actually just his memory of a man that died in Vietnam years ago.

Sources: The Huffington Post