Was camping at the block house camp ground in upper Michigan when I woke up Saturday morning around 630am on the 21st and heard what to me sounded like a humming noise coming from up stream on the paint River. I could hear it coming closer and was confused as to what it was because the river gets wide and shallow and I knew a outboard motor would not be able to operate in the shallow water that was at most a couple feet deep. When standing on the bank listening to the sound get closer a ball of light maybe 15ft in diameter at most was following the path of the river just above the hight of trees but directly in the middle of the river. The ball of light was like nothing I have ever seen it wasn't like a light I have ever seen it was glowing and looked as if the ball was solid but emitting light that was yellowish green and seemed to look like light that was fog in a sense. As it passed over me I could tell the humming was coming from the glowing ball of fog light that passed over and continued directly in the middle of the stream and followed the path of the paint river. I had been up for well over a half hour and was completely sober. This is something that I have never seen anything similar to the light this emitted. It was as if the light emitted was like a fog emitting for it but was bright and clearly soild but couldn't define anything because the light was so bright it obscured what was under the light. It looked to be intentionally following the river as it was directly in the middle and following the bends. The humming is something I have never heard before like a muffled outboard just above a idol.