Almost sheared my thumb off while lubing the chain of my track bike with the wheel going around. Went to hold a rag to the running chain to wipe off the excess grease and the rag and my thumb followed into the rear cog.
Worst hematoma I've ever seen.
Actually this didn't hurt much (if at all) relatively to my collarbone, which was in 4-5 pieces. Lost ~1l of blood but kept all my inner ogans.
Let's never forget that this shit is part of the game guys...