The group behind the infamous Yatta single, made popular here by the infamous Animutation by the name of "Irrational Exuberance". Technically, HappaTai is just a sendup of a stereotypical boy band. The members of this group are actually Japan's best known comedians.
Their one-hit-wonder "Yatta" is actually a political satire made for the sketch comedy show "Silly go Lucky", which is best described as kinda like a Japanese version of "Saturday Night Live". When it firrst aired, Yatta became a popular pop-culture icon on the Internet in North America. But Yatta in general can be described as kinda like a Japanese version of "Lazy Sunday" in a way. But unlike Lazy Sunday, the single actually reached triple-platinum status and got up as high as #6 on the music charts! People usually sing karaoke to this song. The band called themselves "Green Leaves" in English.