An internet "prankster" had to be freed by firefighters after cementing his head inside a microwave oven.
West Midlands Fire Service said it took an hour to free the man after they were called to a house in Fordhouses, Wolverhampton.
Friends had managed to feed an air tube into the 22-year-old's mouth to help him breathe, the service said.
Watch Commander Shaun Dakin said the man "could quite easily have suffocated or have been seriously injured".
Mr Dakin said: "He and a group of friends had mixed seven bags of Polyfilla which they then poured around his head, which was protected by a plastic bag inside the microwave.
"The oven was being used as a mould and wasn't plugged in. The mixture quickly set hard and, by the time we were called, they'd already been trying to free him for an hour and a half."
Crews from the technical rescue team helped with taking the microwave apart, he added.
"It took us nearly an hour to free him," added Mr Dakin.
"All of the group involved were very apologetic, but this was clearly a call-out which might have prevented us from helping someone else in genuine, accidental need."