A Centaur is mentioned but not seen in an episode.
Nothing is known about the species.
A centaur is a mythological creature with the head, arms, and torso of a human and the body and legs of a horse. In Greek mythology, the centaurs were usually said to have been born of Ixion and Nephele (the cloud made in the image of Hera). Another version, however, makes them children of a certain Centaurus, who mated with the Magnesian mares. The most common theory for the origin of the centaur holds that the idea of centaurs came from the first reaction of a non-riding culture, as in the Minoan Aegean world, to nomads who were mounted on horses.