Níðhöggr and the Roots of Yggdrasil
Níðhöggr is a fearsome dragon dwelling in the depths of Niflheim, where he perpetually gnaws at the lowest root of Yggdrasil, the World Tree. Assisted by a multitude of serpents, his destructive efforts represent the forces of decay within the Norse cosmos. Between his lair and the eagle atop the tree, the squirrel Ratatoskr scurries, carrying insults that fuel an eternal rivalry.