Your Friend's signed, marked bill instantly appears in box which is IMPOSSIBLE because it's a sealed box!

They'll try & try but they'll never be able to get it back out!

The Legend of the Wonderfool Box - Once upon a time, a powerful magician about to be executed by the King was granted one last wish. He asked that he might be allowed to live as long a time as it took the King to open a glass box & remove a gold coin which was placed in it.
The King could never ever open the box in his LIFETIME & he ended up losing his throne, his queen & his mind.
The magician died peacefully of old age!
Since those times the mystery Glass Box has been banned & forgotten for centuries.

The Wonderfool Box is the modern version of the original.
A great magic trick & puzzle item.