The performer displays a bottle and a length of rope. The end of the rope is introduced in the mouth of the bottle, then the other end is lifted. The rope comes away as one would normally expect. The rope is again placed into the bottle, and a magic pass is made. Now the bottle is picked up and inverted, but the rope's end stays inside the bottle without falling out. You hold the other of the rope and drop the bottle, and it swings at the end of the rope like a pendulum. Place the bottle down and lift away the rope; once again, it comes free as you would expect.

Demo: