There is no single famous source for this gu clip, and it circulates online as a generic short soundboard effect rather than a line from a film or show. The character 呱 is used in Chinese writing to represent a frog croak, which explains why the sound is filed under that name. Its appeal comes from its brevity, as creators can drop it into edits without breaking pacing, and similar tiny animal sounds have long been reused across meme videos, streams and chat reactions. That simplicity keeps it useful whenever a quick, silly animal cue is needed.