This sound is widely associated with the alien tripod machines from War of the Worlds, especially the 2005 film adaptation directed by Steven Spielberg. The horn became memorable because of its deep, unnatural call and the fear it creates before the machines attack. Online, it spread through dramatic edits, apocalypse memes, and comparison videos where ordinary events are framed like the start of an alien invasion. It remains popular because just a few seconds of the horn instantly signals scale, dread, and a cinematic sense of danger.