In Norse mythology’s Ragnarok, the magical fetter that binds the wolf Fenrir until the final battle is Gleipnir.
The gods commissioned Gleipnir after Fenrir became too dangerous to leave unrestrained. Earlier chains had failed because the wolf broke them, so the gods asked the dwarfs to create a special binding. Gleipnir looked like a thin, soft ribbon, yet it held Fenrir fast.
According to Norse myth, Gleipnir was made from six impossible ingredients: the sound of a cat’s footsteps, a woman’s beard, the roots of mountains, the sinews of bears, the breath of fish, and bird spittle. These things were said to be unavailable afterward, explaining several features of the mythic world.
Fenrir suspected deception and demanded that the god Týr place a hand in his mouth as a guarantee. When Fenrir discovered he could not escape, he bit off Týr’s hand. Gleipnir remains distinct from Ragnarok itself: it restrains Fenrir before the battle, but the wolf eventually breaks free and kills Odin.