Actually, that phrase has been around for a REALLY long time. I've been hearing it my whole life, but it took a Google search today for me to discover that it's been around since at least the 3rd century BC.
Because I'm too lazy to find a good source, here's a Wikipedia page:http://en.wikipedia.org/wiki/Irresistible_force_paradox
Edit: I wasn't going to say it, but
I assumed it was a WoW reference when I heard it in Batman.
is likely to be the most depressing thing I read all week. I'm taking solace in the fact that you figured that couldn't be right and wondered where it really came from. (So, you know, if I misinterpreted the rest of your post, don't tell me.)