The two-note cuco call imitates the common cuckoo bird, whose song was copied by traditional mechanical cuckoo clocks to announce the hour. Those clocks became a familiar household symbol of timekeeping, and their distinctive call is still recognised instantly today. Online, short recordings of the call are shared as a light, instantly understood sound effect for jokes about lateness, schedules, and waiting, rather than as a musical sample or a voice line. Its brevity keeps it useful in memes, cartoons, and short videos where a full clock chime would feel too slow.