The magician wraps a rope around his hand, then four knots appear on the it, then they vanish just as easily. tūnnek.
Joker Magic Magical Knots specifications
Video demo:
The performer shows a rope to the spectators. He coils it up around his hand, ties a small magical knot on it, which makes four knots appear on the rope. He unties the first knot, but to speed things up he coils the rope once more around his hand, and sprinkles some magical salt on it. All the knots vanished!
After this more tricks can be performed with the rope, it can be handed out to the spectators to examine.
Two bonus sleight of hand tricks included in the video explanation.