Demonic Wishing Eye

The demonic wishing eye looks like a giant medallion necklace with a red eye at the center that the Ice King wears around his neck. He claims that his future wife may be marrying him to gain control of it in "When Wedding Bells Thaw." He keeps it on his neck near the ghost pouch.

In "Reign of Gunters", it is revealed that the eye has the ability to create unlimited supply of powerful doppelgangers of the wearer; these doppelgangers are impossible to defeat but still have the will and mindset of the wearer. When one of the Gunter wears it, the penguin doppelgangers gain abilities that allow them to easily take over Ooo, including physical manipulation of the form through face and size and the various transformation of form.

It is also revealed you can buy them at the Wizard Market.

Trivia

 * In the Legends of Ooo game, you can find this in Ice King's Bedroom, it is used to translate Ice King's Spell Book. Though, the name was changed slightly (Demonic Witching Eye).