Gaueko

In Basque mythology, Gaueko is a great black wolfhound that sometimes walks upright. He eats shepherds and their herds and rapes girls. He is called the “Lord of the Black Magic”. His howls can be heard on cold winter nights. In Basque, Gaueko literally means "of the night".
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[Basque] "He of the night." It is a male personification of the Night and all its dangers. If daytime is for the humans and the living, the night is for the spirits and the dead. Thus Gaueko, when finding a man awaken and out at night, will warn him against performing some tasks when there is no light, and will urge him to go home quickly and stay there until sunrise. Nothing will happen if this person obeys, but if he or she defies or despises the night, Gaueko will be angered and punish this human.