Video mystery

I took this video about 8 years ago in Wisconsin. Does anyone have the slightest idea what in the world this is?

Look in the middle of the photo for a view of what it looked like (click on the photo for a larger view). You can see it is an oval shape with bands of darker gray at each end. The size of it was smaller than a pea. You could pick it up and put it in your hand, and it would jump around your palm, but if you blew on your palm, it wouldn't roll or move over unless you blew really hard. It stayed around in the dirt patch where we found it for a few days, and then it disappeared and we never saw anything like it again.