The origin of this elongated Matsui call is not clearly documented, and no specific film, show or creator is reliably credited with it. It circulates online as a short-form reaction clip, shared under stretched spellings like Matsuuuuiiii to match how long the name is held. Its popularity comes from the delulu label attached to it, a slang term for playfully delusional romantic or fandom thinking. Users keep reposting it for exaggerated longing, celebrity worship and joke obsession, where a normal name call would not feel dramatic enough.