FENRIR, or FENRIS  , in Scandinavian mythology, a water-demon in the shape of a huge wolf . He was the offspring of Loki and the giantess Angurboda, who bore two other children, Midgard the serpent, and Hel the goddess of death . Fenrir grew so large that the gods were afraid of him and had him chained up . But he broke the first two chains . The third, however, was made of the sound of a cat's footsteps, a man's beard, the roots of a mountain, a fish's breath and a bird's spittle . This magic bond was too strong for him until Ragnarok (Judgment Day), when he escaped and swallowed Odin and was in turn slain by Vidar, the latter's son .