Alligators hiss as a defensive signal when they feel threatened, inflating their lungs and forcing air out to warn rivals and predators away. Recordings of that behaviour have long been used in nature documentaries and wildlife sound libraries, and short versions later spread to soundboards and meme edits. Because the sound is short, harsh and instantly recognisable as reptilian, creators reuse it far beyond swamp footage, dropping it over pets, toys and people pretending to be territorial for comic effect.