Eyes of Darkness by Tommaso Guglielmi (ACAAN Effect)

The performer shows two decks closed within their boxes. A spectator selects one of them and puts it aside (This deck will be used later). The perfomer asks the spectator to remove the second deck from his box and to check if the deck is a regular deck. At this point the performer instructs the spectator to select a number and a playing card using a very clean procedure with this deck. The spectator for example chooses 31 and Ace of Spades. Now, without the performer touching the decks, the second spector removes the first deck from its box and counts face-up 31 cards in a pile onto the table. The last card will be the Ace of Spades.