Mythical dragons did exist in Nordic folktales. It's no wonder that the Vikings carved dragon heads on the ends of their longships. However, they are vastly different from other dragon myths, like the tales of English knights. For example, the dragons mentioned in the Norse sagas are malevolent creations, like Nidhogg's corpse. Nidhogg lives beneath the roots of Yggdrasil, the Tree of Life, and feeds on its roots.