numa numa (meme)
The Numa Numa dance, a 2004 internet meme spawned from the Romanian-language dance hit Dragostea din Tei by O-Zone.
Both in English and in Japanese, the lyrics were misheard as a mondegreen in those languages. The "lyrics" in Japanese can be found here.
The chorus is misheard as "Drink, drink, yay!", so in Japanese will often be seen accompanied with people drinking alcohol.
Danbooru post #42977 was a popular flash animation of the Japanese version of the meme, illustrating the Japanese interpretation of the lyrics.
External links:
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