This sound is listed as created by Memo under the title Nasii, with the published description giving only the repeated phrase nasi riv riv riv. No source film, show or song is documented for it, so it circulates purely as a user made soundboard clip. Its appeal is the brevity and odd rhythm, which let creators drop it into edits without explaining the reference. It has been kept as a tiny reaction sound rather than a longer meme format, shared mainly where one second interjections work best.