Imagine being able to visually wipe the ink off a playing card - then, under no cover, make it jump back on! As visual as it gets! Welcome to inKcognito.
The spectator selects a card - it is then signed across the face. You ask them whether they have heard of the concept of invisible ink. You show your hand empty. Then, with just a wipe of your hand across their signature, the ink vanishes. The card can be handed out at this point, but you're not done. You take the card back and, with just a shake, and under no cover, the ink jumps back onto the card! You hand the card out and everything can be examined.