Skogul and Geirskogul

In Norse mythology, Skǫgul (Old Norse "shaker" or possibly "high-towering" ) and Geirskǫgul (Old Norse "spear-skögul" ) are valkyrjur who alternately appear as separate or individual figures. Both valkyrjur appear in Heimskringla where they seem to be the same being, and are otherwise listed separately in the valkyrja lists in the Poetic Edda poems Vǫluspá and Grímnismál, the longer of the two valkyrja lists in Skáldskaparmál yet Skǫgul appears alone in the shorter of the two. Skǫgul appears in kennings but Geirskǫgul does not.

Heimskringla
In Hákonarmál, Óðinn sends forth the two valkyrjur Gǫndul and Skǫgul to "choose among the kings' kinsmen" and decide who in battle should dwell with Óðinn in Valhǫll. A battle rages with great slaughter, and part of the description employs the kenning "Skögul's-stormblast" for "battle". Haakon and his men die in battle, and they see the valkyrja Gǫndul leaning on a spear shaft. Gǫndul comments that "groweth now the gods' following, since Hákon has been with host so goodly bidden home with holy godheads." Haakon hears "what the valkyrjur said," and the valkyrjur are described as sitting "high-hearted on horseback," wearing helmets, carrying shields and that the horses wisely bore them. A brief exchange follows between Haakon and the valkyrja Skǫgul:
 * Hákon said:
 * "Why didst Geirskogul grudge us victory?
 * though worthy we were for the gods to grant it?"
 * Skogul said:
 * "'Tis owing to us that the issue was won
 * and your foemen fled."

Skǫgul says that they shall now ride forth to the "green homes of the godheads" to tell Óðinn the king will come to Valhalla. The poem continues, and Haakon becomes a part of the Einherjar in Valhǫll, awaiting to do battle with the monstrous wolf Fenrir.

Kennings
The name Skǫgul is common as a valkyrja name in kennings. Examples include:
 * borð Skǫglar "board of Skǫgul" (shield)
 * dynr Skǫglar "din of Skǫgul" (battle, e.g. in Glymdrápa)
 * eldr Skǫglar "fire of Skǫgul" (sword)
 * gagl Skǫglar "gosling of Skǫgul" (raven)
 * kápa Skǫglar "cape of Skǫgul" (byrnie)
 * veðr Skǫglar "wind of Skǫgul" (battle, e.g. in Hákonarmál)

The name Geirskǫgul does not appear in kennings, perhaps because trisyllabic names are somewhat difficult to handle in the dróttkvætt meter.

Theories
According to Hilda Ellis Davidson, if Skögul means "high-towering", the name "might be a reference to the gigantic size of these beings."