Serial (53R1AL) By Dan Cain (Instant Download)

Imagine...
A spectator chooses a card from a deck or in their mind.

You ask for a dollar bill.

They sign the bill.

Then, as the spectator is holding their signed bill...
...the serial number changes to spell out their chosen card.

THEY CAN KEEP IT AS A SOUVENIR AS PROOF OF THE IMPOSSIBLE!