How about Harry Potter and a great big bloody brick with spikes on the edges, he could go around slowly decapitating people he doesn't like with it. Or not, Im not sure it could be sold to kiddies anymore, or at least not sold without a guaranteed to make your kids wet themselves warning on the outside.

I havent seen the movie but i know that the philosophers stone is a key item in the PS2 game devil may cry, which is an awesome game in its own right, but just thought ide add that as a side note