Magician shows a “Cow” and a “Frog” board. He also introduces an empty envelope and an empty bag. “Cow” and “Frog” are placed into the empty envelope and have the spectator choose either “Cow” or “Frog”… (Let’s say that “Cow” has been chosen…)

“Cow” is placed into the empty envelope..With magical gesture, “Cow” changes into “Frog”. The envelope is shown immediately, but there is nothing left inside….

The bag is opened.. There is “COW” inside the bag! Of course, there is nothing left in the bag, as well…

“Cow” and “Frog” instantly and magically change places!