Jörmungandr

In Norse mythology, Jörmungandr (Old Norse: Jǫrmungandr, lit. 'the Vast gand', see Etymology), also known as the Midgard Serpent or World Serpent (Old Norse: Miðgarðsormr), is an unfathomably large sea serpent or worm who dwells in the world sea, encircling the Earth (Midgard) and biting his own tail, an example of an ouroboros. As a result of it surrounding Midgard (the Earth) it is referred to as the World Serpent. When it releases its tail, Ragnarök (the final battle of the world) will begin.