An eight legged horse born of Loki, Sleipnir is the favored Steed of the God Odin
A riddle from the Poem Heiðreks gátur
36. Gestumblindi said:
"Who are the twain
that on ten feet run?
three eyes they have,
but only one tail.
Alright guess now
this riddle, Heithrek!"
"Good is thy riddle, Gestumblindi,
and guessed it is:
that is Óthin riding on Sleipnir."