The tale begins in the halls of the gods, where the Æsir were preparing for a grand feast. However, they found themselves without a vessel large enough to brew the vast quantities of ale required for such a gathering. The sea deity Aegir agreed to host the festivities, but only if the gods could provide a cauldron of sufficient depth. This was no easy task, for such a vessel was not to be found among gods or men. It was the brave and resourceful Tyr who suggested a solution. He knew of a giant named Hymir, his own step-father, who dwelt at the edge of the sky and possessed a cauldron a mile deep.
Thor, the god of thunder, never one to shy away from a challenge or a journey into the lands of the jötnar, agreed to accompany Tyr. They set out in Thor’s goat-drawn chariot, traveling until they reached the rugged, ice-bound halls of Hymir near the Elivagar. Upon their arrival, they were greeted by Tyr’s grandmother, a monstrous creature with nine hundred heads, and his mother, a beautiful woman who advised the gods to hide beneath the cauldrons in the hall, as Hymir was often ill-disposed toward guests. When the giant returned from his day’s hunting, his frozen beard clattering with ice, he shattered a stone pillar simply by looking at it, but eventually, his wife persuaded him to welcome the newcomers.
The next morning, the hospitality of the giant was already wearing thin. Thor, whose appetite was legendary even among the gods, had consumed two of Hymir’s three oxen for supper the previous night. Hymir grumbled that if they wished to eat that evening, they would have to provide their own food by fishing in the deep waters of the fjord. Thor, unfazed, agreed to go fishing but demanded that Hymir provide the bait. The giant, hoping to humiliate the god, told Thor to find his own bait from the herd of cattle grazing in the high pastures.
Thor strode out to the fields where Hymir’s prize livestock roamed. Among the herd stood a magnificent black ox of staggering proportions named Himinhrjót, a name meaning 'Heaven-Roarer'. The beast was a symbol of the giant's wealth and power. Without a moment's hesitation or the use of his hammer Mjölnir, Thor gripped the ox by its massive horns. With a display of raw, divine strength that made the very earth of the Lofoten peaks tremble, Thor twisted the beast's neck and ripped the head clean off its shoulders. He returned to the shore, swinging the bloody head of Himinhrjót as if it were a mere trinket.
Hymir was appalled by the destruction of his finest animal but said nothing, fearing the thunder god's temper. They pushed off in a small boat. Thor took the oars, and with his mighty strokes, the vessel cut through the freezing waves of the North Sea with unnatural speed. Hymir soon caught two whales and felt satisfied, but Thor refused to stop. He rowed further and further out, beyond the banks where the giants usually fished. Hymir grew uneasy, warning Thor that they were entering the waters where Jörmungandr, the Midgard Serpent, resided—the beast so large it encircled the entire world, biting its own tail.
Thor ignored the giant's pleas and rowed until the shore was a thin line on the horizon. He then took a thick rope and a hook of immense size and strength. He impaled the head of the ox Himinhrjót onto the hook and cast it into the dark, churning depths. The head sank deep into the abyss, down past the shoals of fish and the lightless caverns of the deep sea, until it reached the very bottom. There, the Great Serpent of Midgard lay in the silt. Smelling the blood of the ox, the monster opened its cavernous mouth and swallowed the bait whole.
When the hook pierced the roof of the serpent's mouth, Jörmungandr thrashed in agony, a movement so violent that it caused the oceans to boil and the mountains of Norway to shake. Thor felt the tug and planted his feet so firmly against the bottom of the boat that his legs broke through the wooden planks, and he stood upon the sea floor itself. A tug-of-war began between the protector of mankind and the agent of chaos. Slowly, with veins bulging and his divine rage (ásmóðr) heightening, Thor pulled the serpent upward.
The surface of the water broke, and the terrifying head of Jörmungandr emerged, dripping with venom and sea-slime. Thor stared into the serpent’s burning eyes, and the serpent spat black poison at the god. The sight was so horrific that Hymir turned pale with terror. As Thor raised Mjölnir high, intending to crush the skull of the beast and end its threat to the world forever, the giant panicked. Fearing that the struggle would sink their boat and bring about the end of the world, Hymir reached out with his bait knife and cut the thick line.
The serpent sank back into the depths with a sound like a collapsing mountain. Furious at the loss of his prize, Thor struck Hymir with his fist, sending the giant tumbling overboard, though the giant managed to scramble back into the boat. They rowed back to the shore in a tense, heavy silence. Despite the failure to kill the serpent, the feat of strength Thor displayed by using the head of Himinhrjót remained one of the most celebrated moments in the Eddas, a precursor to the final battle of Ragnarök where Thor and the serpent would meet for the last time.