Borrow a coin from a spectator, have the coin signed, and then have the coin penetrate a filled water bottle. The coin that magically enters the water bottle is truly the borrowed and signed coin. There is no switch of the coin. There is no duplicate coin. The coin that is given to you is the one that ends up inside the water bottle.
The water bottle is gimmicked in a novel way. The video demonstrates how the bottle needs to be gimmicked. It is not that hard to do, but it will require some care and supplies you may not have around the house. Once the coin has entered the bottle, the bottle can be shown from all sides without anything suspicious to see. However, the water bottle cannot be handed out for close inspection.
1st edition 2022, video 14:13