Hearts of Iron IV is a World War II grand strategy game by Paradox Interactive, released in 2016, in which players control a nation through diplomacy, industry and warfare. Justifying a war goal is one of its central diplomatic mechanics, the formal step a player takes before a declaration of war becomes possible. Clips of that moment spread through gameplay videos, streams and strategy memes, where the sound became shorthand for a campaign turning hostile. It remains popular because HOI4 players recognise the context immediately, even without seeing the game screen.