You're in Michigan; it was a wax moth. It is fun to watch the bees chase them out.
I did some splits the other day and had to resort to using some old frames since I'm completely out of hardware at this point (darn bees :-D). Anyways, evidently there were some small wax moths getting started in the the old frames. The bees would grab them in their jaws and carry them away as the worms wiggled about.