The phrase is everyday Japanese spoken in an exaggerated anime and game style, which is why it travels so well outside Japan as a soundboard clip. Short shocked lines like this became staples of meme edits, gaming videos and reaction compilations because the emotion is clear without any setup or translation. Its very brief length lets editors loop the surprise, stack it with other reactions, or use it as a standalone punchline, and it remains popular for moments built around disbelief rather than genuine horror.