Jörmungandr (the Midgard Serpent)

Jörmungandr, the Midgard Serpent, is so vast it is less a monster than a feature of the world. Another of Loki's children, flung by Odin into the deep sea, it grew until it circled the whole earth and lay biting its own tail beneath the waves — the living horizon, the edge of everything. Twice the myths bring it and Thor together, and both times the meeting rings with doom: when Thor goes fishing with the giant Hymir he hooks the Serpent itself and hauls its head from the sea before the line is cut; and at Útgarðr the 'cat' Thor can lift only one paw of is the Serpent in disguise, raised so high its encircling coil nearly comes loose from the world. Their third meeting is the last: at Ragnarök Thor kills the Serpent and then falls dead nine steps away, choked by its venom. The world-circling snake is the Norse image of the limit no strength finally crosses — and of the bound enemy that strength and doom were always going to spend themselves against together.