This sound comes from the 1990 film Home Alone. In the movie, Kevin's mother Kate McCallister realizes on the trip that Kevin was accidentally left at home, then shouts his name in panic before fainting. That moment became a widely reused reaction clip because the delivery is so immediate and exaggerated. Online, creators use it as a shorthand for sudden dread, regret, or a terrible realization, especially in short meme edits and reaction videos.