Eye of Odin
The Eye of Odin was a mystical object created on Avalon, apparently from the actual left eye of Odin. According to the legends that became centered around it, the Eye granted "power and insight." The exact circumstances of its origin are unknown, but the artifact was apparently off Avalon by 975, as the Archmage was hunting for it in his quest for ultimate power.
It eventually fell into the hands of David Xanatos, who added it to his personal art collection. Soon after his release from prison, he donated the Eye to the Metropolitan Museum of Art, so that the city would owe him a favor, and then stole it back in his Steel Clan armor in a scheme to gain control of the Manhattan Clan. Xanatos gave the Eye to Fox as an engagement present, but it transformed her into a exaggerated personification of her innermost self, a vicious were-fox, under the light of the moon. On Halloween night, 1995, Xanatos enlisted the help of the gargoyles to defeat the transformed Fox before the Eye's effects on her metabolism killed her. They succeeded, and as 'payment,' Xanatos gave Goliath the Eye.
The Eye remained in the possession of the Manhattan Clan until it was stolen by an ensorcelled Demona and Macbeth for the Weird Sisters. The Sisters, in turn, gave it to the Archmage, who donned it, transforming him into a vastly more powerful sorcerer. With the power of the Eye, along with the Grimorum Arcanorum's knowledge and the Phoenix Gate's transportation abilities, the Archmage attempted a takeover of Avalon, which was foiled by Goliath and his allies. Goliath forcibly took the Eye from the Archmage, and took both the Eye and the Phoenix Gate with him as he left Avalon, vowing that they would never be used again.
Unfortunately, Goliath was forced to break that vow during the Avalon journey, when the travellers were confronted by Odin himself, who tried "barter and fair combat" to get the Eye back. When Odin held Elisa hostage to force the issue, Goliath was forced to put on the Eye himself to battle him, becoming a towering, god-like being, but it slowly corrupted Goliath's protecting instinct until he became a controlling, sadistic villain. Only when he was about to kill Angela did he realize that the Eye was corrupting him, and he pulled it forcefully off of himself. Odin took the opportunity to reclaim his missing eye, and the Eye of Odin was no more.
The Eye of Odin transformed its wearer into an exaggerated version of their innermost self. It also granted appropriate mystical abilities to its wearer. In the case of Fox, it granted her Eye-created form superhuman strength, speed and agility. The Archmage gained vast mystical power. In Goliath's case, it granted all those granted to the Archmage and Fox, making him into a god-like being. Its chief drawbacks were that it was difficult to remove, giving painful shocks of energy to any who tried to do so, and corrupted the personality of its wearer, turning them cruel and evil.
The Eye of Odin was created by the sorcerers of a power-hungry Viking chieftain as the ultimate magical weapon. Using its powers, including the creation of magical warriors from thin air and transforming its wielders into godlike beings, this Viking's particular band managed to conquer most of Northern Europe and the British Isles by 994. When they attacked Castle Wyvern, they were stopped by the gargoyle defender of the castle, Goliath. The Eye became dormant for 1000 years, finding its way to the Museum of Ancient Artifacts in Manhattan. When Goliath awoke atop Castle Wyvern in 1994, the Eye became active once more, and fell into the hands of the evil gargoyle Demona. She used the Eye to create an army of magically-powered robot soldiers, which she sent against Goliath, but he managed to defeat her legions, and her as well, by destroying the Eye.