As a teenager back in the seventies a friend managed to get a hold of a five foot tall tank of nitrous.
We stashed it in his garage filled a couple of trash bags full of the gas and went thru the connecting door into his house and down to the basement and proceeded to do what teenage boys did at that time play pool and listen to Led Zeppelin .
A little while later when the bags were empty one of the guys “Ernie” volunteered to go up and refill the bags.
When about 10 minutes and he still wasn’t back the boy who lived in the house said If Ernie is wandering around the house I’ll kill him.
So he charged upstairs and we all followed to watch the fun.
when we got to the garage Ernie was lying on the concrete floor in a pool of blood.
Apparently Ernie decided to take the gas straight from the nozzle eventually passing out and hitting his head on the floor splitting the skin on his forehead wide open.
OK now here comes the really good part.
You do know what happens when a a pressurized liquid turns into a gas right ?
At some point after the anesthesia took effect the nozzle got cold enough to freeze to his lip and when he finally fell he left a good portion of his lip behind.