Missile lock-on sounds come from the warning systems used in military aircraft, where a rising tone tells a pilot that a weapon has acquired its target. Similar alerts have appeared for decades in combat flight games, action films and aviation simulations, which is why the beep is instantly recognisable even to people who have never flown a jet. Online, creators reuse the effect as shorthand for targeting, danger or an imminent strike, dropping it into gaming clips, edits and reaction videos whenever they want a moment to feel high-stakes and cinematic.