Self Cutting Cards by Dr. Martin Schwartz

Dr. Schwartz's name means unusual mechanical magic and here is one of his favorites. A deck of cards is removed from the box and a card is freely selected (no force). You now proceed to tell the suite of the card. The card is signed and placed back into the deck. The deck is placed onto the table as the spectator with a waving gesture mysteriously causes the deck to start cutting itself. No strings, loops, magnets, radio control. You are standing away from the table. You remove the cut portion to reveal the signed card. A punch climax for a novel card effect. Just right for close up.

Easy to do. Complete with video instructions