Considering how many blockbuster movies are remakes or adapted from books, comics, or video games these days (16 of the movies in 2013's Top 20 grossing movies worldwide were sequels or adapted from some other work), studios crave the movie rights to popular media. Today's fans are also a lot more aware of how important movie rights are than they were in the past, especially when it explains why Spider-Man (movie rights owned by Sony) and the X-Men (movie rights owned by Fox) can't appear in The Avengers movies (movie rights owned by Disney). Last year's Saving Mr. Banks also demonstrated how difficult it can be for studios to acquire the movie rights to adaptations they want to produce. So when studios finally get their hands on those rights what sometimes follows is years, if not decades, of lawsuits by studios to protect them or to prevent others from trying to claim them. Also, the tricky thing with movie rights to a property is that you use them or lose them  usually a date is set in which the film adaptation must be released or the rights will revert to the original owner (obviously it's more legally complicated than that, but let's keep it basic). Of course, this is Hollywood, an industry not necessarily known for being fair and level-headed. Here are 8 examples of the most ridiculous behind-the-scenes fights over movie rights...