I actually had this kind of fun before- but it was the bronze drain plug in the bilge of a boat. I had surgery and had not removed the plug like I normally did. By the time I got to it, I had to break the ice and reach down into a foot of water below that to a plug that was out of sight and had to be removed by feel. That is when I really appreciated my brilliant decision in the spring to screw the plug in one more time with the rounded off head. "I'll worry about it later."
Finding something by feel doesn't work too well when you can't feel your hands at all.