There are a lot of myths about dangerous mythical creatures, from sirens to the Kraken to the hydra, some of which preyed upon humans. In Maori legend, Te Hokioi was a giant black-and-white bird, with a red crest and huge beak. And just like the Kraken was probably based on a real creature—the giant squid—Te Hokioi was probably a real bird.
That bird would be a Haast eagle, extinct for just 500 years, according to a study in the Journal of Vertebrate Paleontology.