The Oz Key prop used in "Return to Oz".
An Oz Key is a frequent item in Oz-related stories. Generally the key is gold or bronze, with the Oz symbol at the end of its handle. It is used for different purposes, but usually having to do with accessing an important Ozian treasure or getting into Oz itself.
In Return to Oz[]
The Oz Key.
Dorothy Gale finds a key with the Oz symbol in it when working on her farm in Kansas, but Aunt Em dismisses it as evidence of Oz.
Later, when Dorothy and Billina have found their way into Oz, she is cornered against the wall by Wheelers, and finds that it opens a door to the place where Tik-Tok is kept. (Return to Oz)
In Dorothy and the Witches of Oz[]
The Wicked Witch with the Oz Key.
The Wizard of Oz hid the Key to Oz with Dorothy, and she returned to Kansas, so that the Wicked Witch could not get it. The key opens a spell book which contains the Spell of Changing - the most powerful weapon in the world. The Wicked Witches try to get Dorothy to remember where the key is. (Dorothy and the Witches of Oz)
In Supernatural[]
The Key to Oz.
The Key was kept with the "Men of Letters" in their bunker. It was capable of turning any ordinary locked door into a portal to Oz. The Wicked Witch hoped to get the key to bring her armies from Oz into our world. The key was ultimately used to open a portal for Charlie and Dorothy to return to the Land of Oz with, after the defeat of the Wicked Witch. (Supernatural: "Slumber Party")
In Oz: Broken Kingdom[]
Oz keys are used to open gates throughout Oz. There are many such keys, and at times a gate will require - and consume - more than one of them to open. (“Oz: Broken Kingdom”)