Wonder Woman's Invisible Plane
The Invisible Plane was a form of early transport for Wonder Woman. It was later redesigned as an alien object that could take any form the owner desired. In 2011, DC Comics rebooted their universe. Apparently, in this new continuity, the Invisible Plane never belonged to Wonder Woman at all. It was designed by A.R.G.U.S. and is the main means of transportation for Steve Trevor's Justice League of America.
Word of God
A tome containing words that can alter reality in a manner similar to magic when spoken. Many who found the book considered it to be the Word of God because of the great power the words in the book possess. In actuality, it was created by an extradimensional entity which had accidentally left the book on Earth during ancient times.