Show your audience a ring which has a rubber band passed through it. Move the rubber band back and forth.
Then pull the rubber band forward, and suddenly it is freed from the ring, passing right through it!
Your audience can inspect the ring and rubber band, but they will find nothing unusual; the ring and rubber band are whole.
The secret is in how you hold the ring. Start by placing the rubber band on the ring as shown.
Then simply pinch the rubber band inside the ring with your fingers. The wide part of the ring will hide your secret.
Looking at the ring from the front, one gets the impression that the rubber band is passed through the ring. And when moving the rubber band back and forth, you are, of course, only stretching it. Your job is to do this inconspicuously to create the illusion. At the right moment, you release the rubber band with your fingers without changing the way you hold the ring.