The whistle comes from The Hunger Games, the 2012 film adaptation of Suzanne Collins's novel, where Rue, a young tribute from District 11, uses a four-note whistle to communicate with Katniss in the arena. The tune became closely linked to Rue and to the mockingjay signal in the story, and clips of it later spread through fan edits, reaction videos, and short-form posts. It remains popular because the sound is instantly recognisable to fans yet unsettling on its own, making it useful for suspense, stealth, and eerie moments even outside the film.