The name of the Norse serpent that encircles the world is Jörmungandr, also known as the Midgard Serpent. This creature is a child of Loki and grows so large that it wraps around the Earth, biting its own tail. Jörmungandr plays a crucial role in Norse mythology, particularly in the events of Ragnarök, where it battles Thor. Symbolizing the cycle of life and death, Jörmungandr embodies themes of chaos and the interconnectedness of all beings.