A popular brand of soy sauce. Regulars on the Japanese message board 2-Channel came up with a joke superhero, named after Kikkoman sauce, who fights for justice against evil foreign sauces. The flash video for the Kikkoman superhero is popular, even among those who have no idea what's going on in it. (In fact, that probably helps. See: Hi-Ho.)
In the original post, the flash movie was misspelled Kikkomaso
(the katakana for 'n' and 'so' are very similar), and it is still sometimes referred to by that name.