What is "nargun"

According to Gunai/Kurnai tribal legends, the Nargun is a fierce half-human half-stone creature that lived in the Den of Nargun, a cave under a rock overhang behind a small waterfall in the Mitchell River National Park, Victoria, Australia. Aboriginal legend describes the Nargun as a beast that was all stone except for its hands, arms and breast. The fierce creature would drag unwary travellers into its den, and any weapon directed against it would be turned back on its owner.