Young Magneto or some kind of Spider-Man enemy? It's a Sophie Choice, comic book style:
Matthew Vaughn is said to want [Michael Fassbender] for “X Men: First Class.” Fassbender would play young Magneto, the precursor for Ian McKellen’s later character. James McAvoy is already signed to play Young Xavier.
At the same time, Fassbender is being pursued to play the villain in “Spider Man 4,” aka “No Toby Maguire Here.”
Two different movies from Marvel, but two different studios: Fox for the first, and Columbia for the second. He can’t do both.
It's tough decisions like this that make me glad no one ever asks anything of me.