Fermented herring, often sold in cans, "which when opened release a strong smell. Because of the smell, the dish is often eaten outdoors. However, opening the can under water somewhat lessens the smell, as well as prevents the person opening it from being soaked in brine, as the fermentation often builds up a considerable pressure inside the can." So says Wikipedia.
Discussion of the fermented herring starts at around the 10-minute mark, but the first part of the clip is also worth watching, for the discussion of hybristophilia (Bonnie and Clyde syndrome), the origins of heckling and, of course, the hilarious Kate Winslow dream and tomato-and-spider-pizza segments.
"A Japanese study has shown that the smell of a newly opened can of surströmming is the most putrid smell of food in the world, beating similar fermented fish dishes such as the Korean Hongeohoe or Japanese Kusaya." -- Wikipedia