Wikipedia
Akerbeltz
Akerbeltz or Aker ( From the basque language: Aker, billy goat and Beltz, black) is a spirit in the folk mythology of the Basque people. It lives inside the land and it has many elves as servants. In Christianity, Akerbeltz is the live image of the demon. Priests, witches and seers think that he does all type of sexual abuses in the covens he organised.
Nowayadays, instead, it is said that Akerbeltz was an ancient deity which was the animals' protector. The billy goat was also adorated in other European countries and not only in the Basque Country. Some beliefs about this mythologic creature have lasted until nowadays.