The Nome Prince and the Magic Belt.

The Nome Prince Otto finds one of his father's 1908 tunnels under Oz to the Emerald City. Boris, the Cowardly Lion's son, has accidentally released the hold on the display case of the magic belt, and Otto swipes it while the kids try to keep their parents from finding out what happened. When they try to retrieve the belt, Otto transforms them into ornaments in his father's favorite game, leaving Dot to discover who is who.