Nidhogg, also known as ‘Vicious Blow’, or ‘He Who Strikes with Malice’, is a dragon that lives beneath the world-tree Yggdrasil, feeding on the tree’s roots. This is highly injurious to the tree, but the dragon continues his act, intending to pull the tree off its roots, thus pulling the cosmos into chaos, because when he succeeds, he’ll surely be granted a place among giants.

Nidhogg’s body is covered in bright scales, and horns erupt from its head, and a pair of forelegs with massive claws, but it has no back legs, except for a serpentine tail, and wings. The dragon appears in both of the early influential texts about Norse mythology: the Poetic Edda and the Prose Edda.

One day, Nidhogg is destined finally to manage to chew through Yggdrasil’s roots, and when this happens, Ragnarök (the end of the world) will begin.

More Info: mythology.net