LASSO CARD TRICK

You explain that you will now try to do a rare combination of two disiplines within magic. You empty a blue bag for what's inside, a piece of white rope and a deck of cards.

You ask someone to pick a card and shuffle it back in the deck and the drop the deck into the bag. You now lower one end of the rope into the bag, and after a few seconds you lift it up again. The rope has now tied itself around one single card - of course exactly the spectators card.

You get the special solid bag along with the rope and instructions. Use your own playing cards.