The UFO was a bright white light in the sky and was about the size of a baseball, increasing in size at times to bigger than a basketball. We stopped on a over pass off of hwy 29 to watch the object and observed it for about 20 min. The object moved like nothing I have seen before, it would be in one part of the sky one second and in another part the next it was the most unnatural thing I have ever seen. We left and got back on the road it was about 1:30 AM. at about 2:30 I remember I looked in my rear view mirror and saw the object again, like it was following us, I remember we were all afraid, the next thing I remember the sun was coming up and we were driving on the wrong road and we were almost to Madison…We were trying to get to Green Bay.