How Loki wagered his head
Loki, the son of Laufey, out of mischief cut off all the hair of Sif. When Thor discovered this he seized Loki, and would have broken every bone in his body, only he swore that he would get the black dwarfs to make hair of gold for Sif, which should grow like any other hair.
Loki then went to the dwarfs that are called the sons of Ivallda. They first made the hair, which, as soon as it was put on the head, grew like natural hair. Then they made the ship Skidbladnir, which always had the wind with it wherever it would sail. Lastly, they made the spear Gugner, which always hit its mark in battle.
Then Loki wagered his head against the dwarf Brock, that his brother, Eitri, could not forge three such valuable things as these. They went to the forge. Eitri set the bellows to the fire, and bid his brother, Brock, blow. While he was blowing there came a fly that settled on his hand and bit him, but he blew without stopping till the smith took the work out of the fire, and it was a boar, and its bristles were of gold.
Eitri then put gold into the fire, and bid his brother not stop blowing till he came back. He went away, and the fly came and settled on Brock's neck, and bit him more severely than before, but he blew on till the smith came back, and took out of the fire the gold ring which is called Draupnir.
Then he put iron into the fire, and bid Brock blow, and said that if he stopped blowing all the work would be lost. The fly settled between Brock's eyes, and bit so hard that the blood ran down so that he could not see. So, when the bellows were down, he caught at the fly in all haste, and tore off its wings. When the smith came he said that all that was in the fire was nearly spoiled. Then he took out of it the hammer, Mjolnir. He then gave all the things to his brother Brock, and bade him go with them to Asgard, and settle the wager.
Loki produced his articles, and Odin, Thor, and Frey were the judges. Then Loki gave to Odin the spear Gugner, and to Thor the hair that Sif was to have, and to Frey Skidbladnir, and told them what virtues those things possessed.