I'm outlining a possible new screenplay idea, and in order to make it click, I need a MacGuffin. (If you don't know what one is, do a search.) What I want is an object that is very rare, valuable, and one that people would kill for. It could be virtual (such as information -- such as the NOC list in Mission: Impossible), but if it's something physical, it should be small and portable, ideally pocketsized. Any suggestions? Best suggestion gets to name a character!