A spectator selects a card that is shown to everyone except the magician, and the spectator shuffles the card back into the deck. The shuffled deck of cards is then dropped into a brown paper bag. A rope with tassels on either ends is shown and lowered into the paper bag. After a bit of mumbo - jumbo the rope is pulled out and the spectators see that the rope has knotted itself around the selected card.
This is an improved version of an old classic trick that has been improved by the end of the tassels making it seemingly impossible to use gimmicked ends