A few years ago I was mowing around the pond at the house. Using a 5400JD and a 15' Bush Hog Batwing. I believe this area was a rock farm at one time, we have to keep a constant eye out for them they seem to grow right out of the ground. Anyway this particular time just mowing away I hear the hit, quickly turn to look and see nothing.
As I turn back I see my brother-in-law, on the other side of the pond about 75 yards away picking himself up off the ground. I shut off the tractor to ask him what happen. After a string of words, he told me I'd just knocked him down with a rock and held up a rock about the size of a melon. He bruised up pretty bad, hit him in the back left shoulder. It was just luck it didn't kill him.
I still look at the distance and find it hard to believe. I recently bought a Flail and that was part of the reason.