Loki and the Birth of Sleipnir
To protect Asgard and avoid a disastrous bargain with a giant builder, the trickster god Loki transformed into a mare to lure away the stallion Svaðilfari. This act of deception successfully halted the construction of the gods' fortress walls, but resulted in Loki giving birth to the legendary eight-legged horse, Sleipnir.