Because some people have an incurable drive to eat stupid shit. Like Hákarl. The Greenland shark is poisonous, but people in Iceland and Greenland are so hellbent on eating that motherfucker that they bury it in the ground for a few months and then hang it out to dry for another few months. Needless to say it's absolutely revolting, and its only reason for existence is to spit in Mother Nature's face.