Gleipnir, in Norse mythology, a magic cord used to shackle the monstrous
wolf Fenrir. One of the offspring of the trickster god Loki and the giantess
Angerbotha, Fenrir grew so large and so fast that the gods became worried
at the threat he posed to them. Using the argument that they wished merely
to test his strength, they tried to shackle him first with an iron fetter
called Leyding, but Fenrir broke it immediately. Then the gods made a fetter
twice as strong, called Dromi, and, with more effort, Fenrir broke this chain
as well. So the chief of the gods, Odin, sent the messenger Skirnir to the
realm of the dwarfs and had a magical fetter made called Gleipnir. The dwarfs
forged it from the noise of a cat's footfall, a woman's beard, mountain roots,
the sinews of a bear, a fish's breath, and the spittle of a bird. It was
smooth and soft, like a silken ribbon. When the gods presented Fenrir with
this new test, he suspected magic and was reluctant to allow them to put
it on him. The god Tyr put his hand in the wolf's mouth as a pledge of good
faith. Fenrir was unable to free himself from Gleipnir. He bit off Tyr's
hand in his struggle to break it, but the gods were afterwards safe from
the wolf's ferocity.