In Norse mythology, Eikþyrnir is the stag standing on Valhalla’s roof.
The stag appears in the Grímnismál, a poem preserved in the Poetic Edda. Eikþyrnir eats from the branches of Læraðr, the great tree or plant associated with Valhalla. According to the poem, moisture flows from his antlers and gives rise to rivers, linking the animal to the mythic geography surrounding the gods’ world.
Eikþyrnir is frequently mixed up with Heiðrún, the goat also placed on Valhalla’s roof. The goat supplies mead for the einherjar, while the stag is connected with water and rivers. The names Dáinn and Dvalinn belong to other deer in Norse mythology, especially the stags associated with the world-tree in later descriptions.