Eggs

Me and my buddy tried to hard boil an egg in the microwave in 8th grade. We thought it'd make a mess so we inverted a glass over it, set it for 10 minutes and went to the living room and forgot about it. Pretty sure we were watching one of his dad's porno tapes. Not even a good one.
Boom!
We looked at each other ran back in there and it had destroyed the glass and was a complete pain to clean up. Not a good smelling thing either