The shishishishi laugh comes from One Piece, where characters are known for highly distinctive, repeated-syllable laughs that signal their personality before they even explain themselves. This drawn-out, sneaky version was clipped from the anime and began circulating on soundboards and in fan edits as a standalone reaction. Anime fans recognised it instantly, while other viewers picked it up as a general smug or teasing laugh for memes and short videos. Its length and repetition keep it useful today, because creators can cut a short burst or stretch it for comic discomfort.