”Jenny Greenteeth is a figure in English folklore. A river hag, she would pull children or the elderly into the water and drown them. She was often described as green-skinned, with long hair, and sharp teeth.
She is likely to have been an invention to frighten children from dangerous waters similar to the Slavic Rusalka, the Kappa in Japanese mythology, or Australia's Bunyip, but other folklorists have seen her as a memory of sacrificial practices.”