I've found 5 magician coins so far and one was just like this. What happened is someone put the back half on backwards and it got stuck. To release it, put it in the freezer for 20 minutes or longer, then try shaking it hard in a "thick" glass container. Pyrex storage containers with lids work nicely. Recycled spaghetti jars break! Or you could buy a bang ring for it. It's an amazing magic trick and fairly easy to perform. Banging it in the jar might ruin the coin.