Cameron's Spider-Man "scriptment," which is a long film treatment with dialogue and screen direction, has become something of a Hollywood legend. According to Rebecca Keegan's book The Futurist: The Life and Films of James Cameron (via SlashFilm), Spidey creator Stan Lee absolutely loved it. Ultimately, many elements of the script—which has been leaked and even illustrated online—made it into the Sam Raimi-directed film that ultimately saw release in 2002, though Cameron never received even informal credit. See if any of this rings a bell: Peter's fever dream/waking up not needing his glasses; Mary Jane as his love interest; Uncle Ben's carjacking death; Peter's indifference while an employer gets robbed; and most notably, Spider-Man's organic, not man-made web shooters. If you're now saying to yourself, "Wait, that's like, the whole Tobey Maguire movie"…yeah, it pretty much is, and those elements were all in Cameron's version.
But he also has Peter peeping in Mary Jane's window while she gets dressed, then later shows them having sex on the Brooklyn Bridge while Peter describes the creepy, and frankly, quasi-rapey ways that spiders mate. Uh, what? Also, Peter uses intense profanity throughout the story, to the point that it would be completely inappropriate for kids (and most likely R-rated, as the majority of Cameron's films had been to that point). Production never advanced far enough for a final, greenlit screenplay to get developed, so who knows whether Cameron could have been persuaded away from the edgier stuff, although his history suggests he would have wanted to make Spider-Man his way or not at all.