Fafnir was a European Dragon in the Norse Mythology. Fafnir was originally a dwarf, the son of Hriedmar and brother of Otir and Regin, but got transformed into a dragon by the ring Andvarenaut. Fafnir had stole a fortune given to the dwarves by the gods as a ransom for Otir's death, and the ring Andvarenaut was in the fortune. The ring then transformed him into a greedy dragon that guarded his treasure to his death. He later died at the hands of Sigurd Fåvnesbane. Sigurd, urged on by Regin, cooked Fafnir's heart and consumed it, giving him useful wisdom(such as the fact that Regin wished to murder him.
The Fafnir myth and this Volsungsaga gave rise to the epic Ring Cycle of Wagnerian operas. This in turn inspired J.R.R. Tolkien, whose character of Smaug is not dissimilar to Fafnir.