Is it The Special Metallic INK That Does It?
5 Different cards are shown. The audience is told that the backs of these 5 cards are printed with a special metallic ink. That this ink picks up thought waves & converts it to electric current. Now spectator just thinks of a card. The cards are laid out in row, face down. You touch each card, one by one. Finally, one gives you an electric jolt! You remove that card & you've found his thought of card. NOW FOR THE KICKER. Spectator turns over the remaining 4 cards. They all have changed to HIS CARD!
EVERYTHING CAN BE EXAMINED! Comes with an alternate "sucker" climax.