Sleipnir moves like nothing you’ve ever seen: neither horse nor centipede, he bunches and stretches in two rippling phases. A wave. An earthquake. And fast.

The good thing, of course, is while he’s getting all that horse up to speed a desperate stable boy can just about keep up. Ehrich pelts madly and snatches the bridle–there! He’s got it, but they’re on Bifröst now, slick as rain, and he’s sliding toward its fiery rails–

Sleipnir takes the bit in his teeth, jerks him up with one contemptuous toss of his head, and Ehrich is riding the horse of the gods.