"The Cats of Ulthar" is a short story by H. P. Lovecraft, written June 15, 1920.
This tale tells of the forming of the law "that in Ulthar no man may kill a cat". Previously to this an old cotter and his wife took great delight in slaughtering the cats of their neighborhood in some unknown yet horrid manner. After they kill the kitten of Menes, an orphan of the strange wanderers who visit the town, he utters a strange prayer before he and his people disappear forever that evening. In response to that prayer that night the cats of the town descend on the old cotter's house, witnessed by Atal, and presumably kill and eat them in retribution.
Ulthar's cats were supposed to be able to jump at the moon through the houses' roofs.