You want a hands off effect you can do under challenge conditions, where the deck is shuffled by the crowd before, during and after, where two cards are absolutely freely chosen and cut back into the deck by the spectators, where you never touch the cards, and yet you can still unfailingly stab smack between their two chosen cards.

Watch the effect first and then try to figure it out...

This takes the Koran Miracle Stab to new heights, truly an impossibility... and best of all it's ENTIRELY SELF WORKING! (shhhhhh)