Þór and Geirroð
One day, for fun, Loki took Frigg's falcon suit and went flying. Wearing the suit, he could fly over any of the nine worlds. He ended up in Jötenheim, the land of the giants, and chose to rest on a wall outside the hall of Geirroð, a giant. Geirroð saw the bird and ordered a servant to climb up the wall and catch the bird. Loki saw how long and difficult a climb it would be, so he waited until the last moment before flying away, just to annoy the servant.
At the final moment, Loki found that his feet were stuck and that he could not fly. When the bird was brought before the giant, Geirroð could see by the falcon's eyes that it was a person inside, and he demanded to know who. Loki stayed silent. Geirroð shut the falcon in a box without any food. After three months, Loki decided to speak. Geirroð offered Loki his life in exchange for bringing Þór to Geirroð's hall without Þór's hammer, Mjöllnir, or his belt of strength, or his gloves of iron. Loki agreed to the bargain and swore an oath to bind it.
Upon returning to Ásgarð, Loki convinced Þór to travel with him unarmed across Jötenheim to Geirroð's hall. On their journey, they stopped at the house of a giantess. She warned Þór about Geirroð's blood-thirsty nature, and she lent him a belt of strength, a staff, and some iron gloves.
their journey, Þór and Loki
came to the river Vimur. Þór buckled on the belt,
grabbed his staff, and set off across the river, with Loki holding
fast to the belt. But midway across the river, the level of the
water suddenly rose, quickly reaching Þór's shoulders
and threatening to drown him. He looked about, and saw Geirroð's
daughter standing astride the river. She was making the river
rise by pissing into it. Þór sought to dam it at
its source, and threw a rock at her, blocking the flow. He waded
to the opposite bank, and heaved himself up onto dry land.
Arriving at Geirroð's hall, Þór and Loki were given accommodations in a goat-house. Inside was only a single chair. Þór sat in it, and immediately the chair began to lift him, until it pressed him against the roof, threatening to crush him. Þór used his staff to push himself down and away from the roof, until there was a crack and a scream. Under the chair were two of Geirroð's daughters who had been pushing up, but who now had broken backs.
Geirroð summoned Þór to the hall for games. As Þór and Loki entered, Geirroð
used a pair of tongs to pick up a red hot ingot of iron from the
fire and to fling it at Þór. Protected by his iron
gloves, Þór caught the missile, and flung it back
at the giant. The giant had taken refuge behind a iron pillar.
But the ingot crashed through the pillar, blazed through Geirroð, killing
and then passed through the wall behind into the ground.