"The Theft of Thor's Hammer," as told by Thomas Bulfinch in The Age of Fable:
Once upon a time it happened that Thor's hammer fell into the possession of the giant Thrym, who buried it eight fathoms deep under the rocks of Jotunheim. Thor sent Loki to negotiate with Thrym, but he could only prevail so far as to get the giant's promise to restore the weapon if Freya would consent to be his bride. Loki returned and reported the result of his mission, but the goddess of love was quite horrified at the idea of bestowing her charms on the king of the Frost giants. In this emergency Loki persuaded Thor to dress himself in Freya's clothes and accompany him to Jotunheim. Thrym received his veiled bride with due courtesy, but was greatly surprised at seeing her eat for her supper eight salmons and a full grown ox, besides other delicacies, washing the whole down with three tuns of mead. Loki, however, assured him that she had not tasted anything for eight long nights, so great was her desire to see her lover, the renowned ruler of Jotunheim. Thrym had at length the curiosity to peep under his bride's veil, but started back in affright and demanded why Freya's eyeballs glistened with fire. Loki repeated the same excuse and the giant was satisfied. He ordered the hammer to be brought in and laid on the maiden's lap. Thereupon Thor threw off his disguise, grasped his redoubted weapon, and slaughtered Thrym and all his followers.