Nidhogg is a mythical creature from what mythology?

Nidhogg is a mythical creature from Norse mythology. In Norse mythology, Nidhogg is a fearsome dragon or serpent-like creature that dwells in the roots of the world tree, Yggdrasil. It is said to continuously gnaw on the tree's roots, seeking to destroy it. Nidhogg represents chaos, evil, and decay, and is often depicted as an antagonist in various Norse tales and legends.