Chapter XII: Section II: The Origin of the Giants (rhimthursar)

The first beings came into existence in the following manner: When those rivers that are called Elivagar, and which flowed from the spring Hvergelmer, had flowed far from their spring-head the venom which flowed with them hardened, as does dross that runs from a furnace, and became ice. And when the ice stood still, and ran not, the vapor arising from the venom gathered over it and froze to rime, and in this manner were formed in the yawning gap many layers of congealed vapor piled one over the other. That part of Ginungagap that lay toward the north was thus filled with thick and heavy ice and rime, and everywhere within were fogs and gusts; but the south side of Ginungagap was lightened by the sparks and flakes that flew out of Muspelheim. Thus while freezing cold and gathering gloom proceeded from Niflheim, that part of Ginungagap which looked toward Muspelheim was hot and bright; but Ginungagap was as light as windless air; and when the heated blast met the frozen vapor it melted into drops, _and by the might of him who sent the heat_,[29] these drops quickened into life and were shaped into the likeness of a man. His name was Ymer, but the frost-giants called him Aurgelmer. Ymer was not a god; he was bad (evil, _illr_), as were all his kind. When he slept, he fell into a sweat, and from the pit of his left arm waxed a man and a woman, and one of his feet begat with the other a son, from whom descend the frost-giants, and therefore Ymer is called the old frost-giant (Rhimthurs). Thus the Elder Edda, in the lay of Vafthrudner:

Countless winters
Ere earth was formed,
Was born Bergelmer;
Thrudgelmer
Was his sire,
His grandsire Aurgelmer.

From Elivagar
Sprang venom drops,
Which grew till they became a giant;
But sparks flew
From the south-world:
To the ice the fire gave way.

Under the armpit grew,
’Tis said, of Rhimthurs,
A girl and boy together;
Foot with foot begat,
Of that wise giant,
A six-headed son.