What is "hrungnir"

Hrungnir ( Old Norse "brawler") was a jötunn in Norse mythology, slain by the god Thor with his hammer Mjölnir. The account is documented in the Skáldskaparmál, in the Prose Edda by Snorri Sturluson.

Prior to his demise, Hrungnir engaged in a wager with Odin in which Odin stakes his head on his horse, Sleipnir, being faster than Hrungnir's steed Gullfaxi. During the race, which Sleipnir wins, Hrungnir enters Valhalla, and there becomes drunk and abusive. After they grow weary of him, the gods call on Thor to battle Hrungnir.