There are a lot of dragons in Norse mythology. Perhaps the greatest is Jormungandr, the World Serpent. The second greatest is Fafnir, who fought the great hero, Sigmund.
But the third greatest (and relishing in his lowly position) would be Nidhogg (also called Níðhöggr).
The Name Nidhogg
Like all creatures, gods, and mortals in Norse mythology, Nidhogg's name tells us exactly who he is. His name itself is a kind of kenning.
Nīþ is the first syllable for the word Nidhogg, and it plays a very important role in Norse society. You see, nīþ means a social stigma in Norse and Germanic culture. It implies that a person has suffered a great loss of honor and is, in fact, a villain. Being called a nīðing (níðingr/ᚾᛁᚦᛁᚴᛦ in Old Norse, nīðing, nīðgæst in Old English, or nidding in Old Germanic). Modern Dutch and German even has similar sounds which imply hate, envy, or greed.
Anyway, anything having to do with nīþ implies unmanliness, cowardice, villianry. If people called you nīþ to your face (and it was expected if you were known to be a niding), you were required to fight them. You could challenge them to take their words back or you would murder them. If you did not engage in physical contact with the accuser, however, it was known that you were a coward.
In physical representations of nidings, they are often represented by a single pole called a nidstang or niding pole. If two poles were placed together, it suggested that the man or men accused of nīþ were also homosexual.
But let's get back to our cowardly serpent.
Yggdrasil's Own Pest
There are a number of pests that live in Yggdrasil, so Nidhogg is by no means lonely. There are four stags, at least seven other great serpents, an eagle who lives at the top, and even a squirrel named Ratatoskr.
From the Völuspá via the Bellows' translation:
Nidhogg in Modern Culture
If you are a big gamer, chances are when you saw the word, 'Nidhogg', you probably pictured this:
Nidhogg lends his name to a lot of video games, including World of Warcraft, Ragnarok Online, Age of Mythology, and Final Fantasy XIV. He is also the inspiration for Alduin in The Elder Scrolls V: Skyrim.
The screenshot above comes from the game Nidhogg, where you and an opponent vy for the chance to be devoured by the serpent.
And if you're super, duper into dragons, sex toy site ZooFur makes a dildo named after our cowardly boy. I think getting fucked by a dragon is the literal definition of metal.
Unlike Jormungandr, Nidhogg doesn't have an ancient symbol. But many modern artists have designed their own, oft times incorporating Yggdrasil, Nidhogg's home.