The Unbinding Stone of Oshemar was an relic that features in Thor: The Deviant Saga.
It was originally created by the savant supreme Oshemar of the Caldaran Dominion when it was involved in a war against the Sextus hive. This conflict had lasted for millennia which saw Oshemar's enemies created protections against conventional weapons. Thus, the scientist developed the Unbinding Stone that operated by repealing the laws of physics thus loosening reality itself until it spooled away into nothingness. Using the weapon, he turned it against the Sexus homeworld and they were destroyed. However, the weapon developed a hunger and began feeding on everything around it which led to the destruction of Oshemar's own continuum as a result. He managed to survive but came to see the stone as a cirse and sin.
Travelling to Asgard, he came before Odin and Thor where he relinquished the weapon to them. Oshemar would shortly perish which saw Odin take the stone as a weapon for the Asgardians despite Thor's disapproval. Secretly, Odin kept the weapon and hid it beneath the Imperial Palace alongside other relics that were too dangerous. The Deviant Ereskighal journeyed to ruined Asgard in order to plunder the Golden Apples of Idunn to use them to cure a plague that was being suffered by her people. Whilst there, she encountered Thor who barred her entry but she managed to enter into the forbidden vaults where she was attacked by the talisman guardian. Whilst Thor protected her, she encountered the Unbinding Stone which she stole as she knew it was an object of power.