Scandinavian rotten fish!
Surströmming, "soured (Baltic) herring"), known colloquially as Scandinavian rotten fish, is a northern Swedish dish consisting of fermented Baltic herring. It is similar to kusaya. Similar fish is made world wide. Surströmming is sold in cans, which often bulge during shipping and storage, due to the continued fermentation. When opened, the contents release a strong and sometimes overwhelming odour, which explains why the dish is often eaten outdoors.