2.17. Two men are found dead outside of an igloo. (SK original)

2.17 answer: The men have gone spelunking and have taken an Igloo brand cooler with them so they can have a picnic down in the caves. They cleverly used dry ice to keep their beer cold, not realizing that as the dry ice sublimed (went from solid state to vapor state) it would push the lighter oxygen out of the cave and they would suffocate.