When they were younger they were humiliated for releasing gas and when they were older they learned of the butter a food item that drastically increases the amount of gas released by humans instead of decreasing it as its intended purpose, and the two planned on using it to cover the whole world in gas using missiles but not before feeding Narao and Yosuru the butter 2 and by the end of the movie they swell up with gas but they had no regrets and decided to do carry on doing things togther