This type of question mark sound effect is widely used across short-form meme edits, gaming clips, and reaction videos as a fast audio cue for confusion. Rather than pointing to one famous source, people usually know it by function and search terms, not by a character or scene. It spread because editors needed a simple way to mark doubtful moments without dialogue, much like a ding sound effect or a dramatic dun dun dunnnnnnnn sting. Its meaning is instantly understood, which keeps it useful in many formats.