Replying to Battle to the Death

A cage match, a superhero in each corner: The Incredible Hulk, Batman, Spiderman and Thor. Who lives?

I've thought about this for like a week (I know, I'm a loser), and here's what I came up with:
Spiderman will go to the top corner of the cage to observe, The Hulk will demolish batman, Thor will kill The Hulk, and just as Thor turns around to kill Spiderman, a web takes Thor's hammer, and Spiderman wins. Of course, if Spiderman can't get Thor's hammer, Thor will win.