bunyip, in Australian Aboriginal folklore, a legendary monster said to inhabit the reedy swamps and lagoons of the interior of Australia. The amphibious animal was variously described as having a round head, an elongated neck, and a body resembling that of an ox, hippopotamus, or manatee; some accounts gave it a human figure. The bunyip purportedly made booming or roaring noises and was given to devouring human prey, especially women and children. The origin of the belief probably lies in the rare appearance of fugitive seals far upstream; the monster’s alleged cry may be that of the bittern marsh bird.