2. Stan Lee Is The Watcher - Marvel Cinematic Universe
The Crazy Theory: Stan Lee has cameoed in pretty much every film under the Marvel banner (except, for some reaon, X-Men 2) with increasing screen time. Hes been a wartime general, Hugh Hefner lookalike, Willie Lumpkin (The Fantastic Four's postman) and even himself. But some would suggest all these people are actually all the same character; the mysterious Uatu.
Why It Cant Be True: Better known as The Watcher, Uatu is part of a species who catalogue the universe for future species. And, of course, hes the one charged with observing Earth. Originally not meant to interfere with us, Star Trek style, he eventually works with The Fantastic Four against Galactus. Pretty cool character, huh? Given the hidden nature its easy to see why Lee could be playing him and it explains the ridiculousness of his recurring cameos. They even look alike if you turn down your computer brightness and squint. But come on. Lee's cmaeos little in jokes that are a more obvious version of Bruce Campbell in Raimis films. In fact, I buy the equally barmy notion that Campbell was an early Mysterio who kept happening upon Peter Parker much more than this. Thankfully I dont think many people take this one too seriously, but no doubt theres some out there expecting Age Of Ultron to have him pop up in a post credit sting.