Switch Up by Danny Weiser

From the mind of Danny Weiser comes a SUPER, visual and unique revelation to take the magic world by storm! 'The Switchup' is a hyper visual ink revelation that changes on the front of a card box right in front of a spectator's eyes... AND the card box is then handed over immediately for examination - Wow! Audience tested, this revolutionary gimmick will fry anyone who gets a chance to 'Switchup'!!!!!!!!

Sample routine - A card is chosen by the spectator. You mention that you have a prediction on your card box. You show your prediction to be a question mark. In the blink of an eye, the question mark changes into the spectator's chosen card, for example 5H.