Black Dog of Aylesbury

Backstory, History and Lore
A man who lived in a village near Aylesbury in Buckinghamshire would go each morning and night to milk his cows in a distant field. One night on his way there he encountered a sinister black dog, and every night thereafter until he brought a friend along with him. When the dog appeared again he attacked it using the yoke of his milk pails as a weapon, but when he did so the dog vanished and the man fell senseless to the ground. He was carried home alive but remained speechless and paralytic for the rest of his life.