In Norse mythology, Hyrrokkin ("Fire-Smoked", possibly referring to a dark, shrivelled appearance) is a giantess. She appears to be depicted on one of the surviving stones from the Hunnestad Monument near Marsvinsholm, Sweden called DR 284.
At Baldr's funeral
It is told in Snorri Sturluson's Gylfaginning that at Baldr's funeral his wife Nanna died of grief and was placed alongside him on his pyre, thus joining her husband in Hel. Hringhorni, Baldr's ship, was the largest of all such vessels and was to serve as the god's funeral ship. No one, however, could seem to launch the boat out to sea.
The gods then enlisted the help of Hyrrokkin, who came from Jötunheimr, arriving on a giant wolf with vipers as reins. When she dismounted, Odin summoned four berserks to look after the animal but they were unable to control it without first rendering it unconscious. With her seismic strength, the giantess rolled the boat into the water. This caused the earth to quake and the rollers to set on fire, which angered Thor. He was about to kill Hyrrokkin with his hammer Mjöllnir, but the other gods insisted that he spare her.
The Æsir then took the dead body and bore it to the seashore, where stood Baldur's ship Hringhorn, which passed for the largest in the world. But when they wanted to launch it in order to make Baldur's funeral pile on it, they were unable to make it stir. In this conjuncture they sent to Jotunheim for a certain giantess named Hyrrokin, who came mounted on a wolf, having twisted serpents for a bridle. As soon as she alighted, Odin ordered four Berserkir to hold her steed fast, who were, however, obliged to throw the animal on the ground ere they could effect their purpose. Hyrrokin then went to the ship, and with a single push set it afloat, but the motion was so violent that the fire sparkled from the rollers, and the earth shook all around. Thor, enraged at the sight, grasped his mallet, and but for the interference of the Æsir would have broken the woman's skull.