The Midgard-serpent vomits forth venom, defiling all the air and the sea; he is very terrible, and places himself by the side of the wolf. [...] Thor gets great renown by slaying the Midgard-serpent, but retreats only nine paces when he falls to the earth dead, poisoned by the venom that the serpent blows on him.

- Prose Edda (The Fooling of Gylfe, XVI)