There is a very well known and widely believed local legend that talks of a demon or spirit which protects one of the rivers nestled between the trees not far from [Town Name]. It's said that anyone who disrespects the river will have their toes stolen by the creature.
What is lesser known is that the demon isn't a demon at all! It is actually the crochety old man [name] who has built his home in a small cave beneath the riverbed and who despised visitors. He prefers isolation and becomes enraged when he hears anyone too close to home, and sneaks out from his den to attack whatever body parts are in reach first. It just so happens to usually be toes.