Mission: Impossible III was silly but enjoyable. At the centre of the plot is an item called the "rabbit's foot", and early in the movie we get this tremendous non-explanation of what it is, made only more excellent in its delivery by Simon Pegg:

Uh, it's all got to do with the 'rabbit's foot'.

(Cruise: The rabbit's foot?) Pegg: Well, I'm assuming it's a code word for something he's about to sell to an unspecified buyer--for 850 million dollars, by the way. Or maybe it's not it's not a code word. Maybe it's just a really, really expensive bunny appendage.

(Cruise: you have any idea what it is?) Pegg: It's interesting. I used to have this professor at Oxford, okay. Dr Wickham. He always seemed like... he was this massive fat guy, big huge guy, we always used to call him [laughs] you know, well, I won't tell you what we called him. He taught biomolecular kinetics and cellular dynamics, and he used to sort of scare the underclassman with this story about how the world would eventually be eviscerated by technology. You see, it was inevitable that a compound would be created that he referred to as the 'anti-god'. It was like an accelerated mutator, you know, a sort of, uh, an unstoppable force of destructive power. It would lay waste to everything, to buildings and parks and streets and children and ice-cream parlours, you know? So whenever I see a sort of rogue organisation, willing to spend this amount of money on a mystery tech, I always assume it's the anti-god. End of the world kind of stuff, you know. But no, I don't have any idea what it is. I was just speculating.