Sleipnir

In Norse mythology, Sleipnir (Old Norse "slippy" or "the slipper") is an eight-legged horse ridden by Odin. Sleipnir is Odin's steed, is the child of Loki (in the form of a mare) and the stallion Svaðilfari. Sleipnir is described as the best of all horses, and is sometimes ridden to the location of Hel. Sleipnir is attested in the Eddas, compiled in the 13th century from earlier oral sources and 8th-century images of an eight-legged horse have been found in Sweden.

Sleipnir in "The Old Grind"
Sleipnir carried Odin and Fenia from northern Francia to Valhalla, and later from Valhalla to Orkney.