Sleipner

Sleipnir (Old Norse: Sleipnir) is Odin's horse and the finest and fastest in all the nine worlds. He is grey and has eight legs. His origin is unusual: Loki transformed into a mare to distract the stallion Svaðilfari while a giant (disguised as a builder) was constructing Asgard's walls. Loki became pregnant and gave birth to Sleipnir, whom he presented to Odin. Sleipnir can gallop over sea, through air, and all the way to Helheim. It was on Sleipnir that Hermóðr rode to Helheim after Baldur's death.