The King of Elfland's Daughter by Lord Dunsany

The troll had found Orion in his castle and had laid his plan before him. Briefly the plan was to have more whips for the pack. For one alone could not always guard every hound from straying when they went to the boundary of twilight, where but a few yards away lay spaces from which if a hound ever came home, as lost hounds do at evening, it would come home all worn and bedraggled with age for its half hour of straying. Each hound, said Lurulu, should have its troll to guide it, and to run with it when it hunted, and be its servant when it came home hungry and muddy. And Orion had seen at once the unequalled advantage of having each hound controlled by an alert if tiny intelligence, and had told Lurulu to go for the trolls. So now, while the hounds were sleeping on boards in a doggy mass in each of their kennels, for the dogs and the bitches dwelt each in a separate house, the troll was scurrying over the fields we know through twilight trembling on the verge of moonlight, with his face turned toward Elfland.

He passed a white farmhouse with a little window towards him that shone bright yellow out of a wall pale blue with a tint that it had from the moon. Two dogs barked at him and rushed out to chase him, and this troll would have tricked them and mocked them on any other day, but now his mind was full to the brim with his mission, and he heeded them no more than a thistledown would have heeded them on a windy day of September, and went on bouncing over the tips of the grasses till the pursuing dogs were far behind and panting.