Gungnir is the Spear of Odin and is also referred to as the "Spear of Heaven". It is an ancient weapon made of the Uru metal which was unique to the Asgardian Dimension. The three-pronged spear is of unknown origin, and predates the last three incarnations of Odin himself. At Odin's "birth" at the dawn of Asgardian history, he found Gungnir on the Plains of Ida and used it to focus his power to fashion Asgard as it was known before the most recent Ragnarok.
In the most recent siege on Asgard, Norman Osborn sent the Thunderbolts to retrieve the Spear from the treasure vaults in the city of Asgard. A team of Thunderbolts located the spear and began extraction when a team of "Mighty" Avengers located them and engaged them in battle. The Thunderbolts member Paladin retrieved the spear and threw it at the Vision who it managed to harm even in his intangible state. It passed through the Vision and destroyed the top of the treasure vault the two teams were fighting in. The Avengers had the upper-hand until Scourge gained control of the Spear and used it to amputate the left arm and leg of U.S.Agent. Osborn called for the Thunderbolts to bring the spear to his location when Paladin had a change of heart, shot Scourge in the face and confiscated the spear and with the aid of Ant-Man and the remaining Avengers they overpowered the last three Thunderbolts and snuck out of the ruins of Asgard in the confusion that the Siege was causing. When the spear was last seen it was still in Paladin's possession as he was hiking down the mid-western highways of Oklahoma away from the ruins of Asgard.