Nanny Rutt is a character in an English cautionary tale associated with Nanny Rutt's well.
According to the story, a girl went off into the woods to meet her lover at the source of the well. On the way, she met an old woman with a shawl over her face, who warned her about the dangers of the woods for young women eloping without permission. But the girl didn't listen and ran into the woods. After waiting for hours she realized he was not coming and tried to leave, but it was dark and she got lost. Eventually she came to a stone building, little bigger than a shack. Outside was the old woman, but she was not wearing the shawl, revealing her hideous face. The girl was never seen again.
The true nature of Nanny Rutt is unknown, whether she is a demon, a witch or something else entirely.