The Kelpie of Glen Keltney

The common story runs that several children climb onto the horse's back, one boy stays behind to pet it and his hand sticks to its neck, and in some versions he cuts off his fingers or hand to get free while the others are carried into the water and drowned. Gregorson Campbell thought the tale was a pious device to keep children from wandering on Sundays. Wikipedia does not give a named victim, farm or date for the Keltney version, so this is a general tradition tied to the glen.