His Dad was trimming his beard with the clippers, The Boy was "helping" and at one point he held the clippers for his Dad. He decided to find out how the vibration would feel against his forehead. He liked it quite a bit and before he knew it, or his Dad could stop it, he ran the clippers across the side of his head. Cutting his hair to about an eighth of an inch. But that isn't were he stopped, he moved the clippers almost to the top of his head and clipped another strip of hair. Dad told him to come and show me what he had done.
After looking at it and discussing what needed to be done, it was decided that the only thing that could be done was to cut the rest of his hair to the same length. It's shorter than I would have liked, but it will grow out again.
Here are some pictures.