Jenny Greenteeth

Origin
Jenny Greenteeth is a figure in English folklore. A river hag, similar to Peg Powler, she would pull children or the elderly into the water and drown them. She was often described as green-skinned, with long, black hair, and sharp teeth.

She is likely to have been an invention to frighten children from dangerous waters but, other folklorists have seen her as a memory of sacrificial practices.

The name is also used to describe pondweed or duckweed, which can form a continuous mat over the surface of a small body of water, making it misleading and potentially treacherous, especially to unwary children. With this meaning, the name is common around Liverpool and south west Lancashire.