A few winters ago I went to tie one a chubby darter over the hole and it accidental slipped out of my hand and swam perfectly down the hole with no line attached to it.
My uncle and I were chopping a hole in the ice one winter when he dropped the ax down the hole it was not too deep, and as luck would have it, the ax landed with the head down and handle up. After a bit of effort we were able to rope it and bring it back up with his larrette.
I had a buddy drop the rubber stopper that holds the camera cord on the tripod down the hole while setting up the underwater camera.
One winter I also lost an ice rod down the hole. I had bait on it and set it up, what I thought was securely in a snow bank, and went to get some item just a little ways away. When I got back, no rod, just a hole in the snow bank where I placed the butt of the rod and a drag mark across the snow and into the hole.
Now I always have my set rods in a substantial rod holder.
WW