Shrinking Coin

Basically just two Bobo Switches and a false transfer. But in terms of effect this is cute. Any regular size is boring. Growing and shrinking stuff makes it funny... or at least interesting. I've done this for normal people often enough to know that they love it. Why is that so? The premise. It is not just a vanish and a reappearance. The object is actually transformed. It is shrunken down and stays that way. Try it with different objects. Coins are great, but if you do this with SD cards... Starting with a big SD card, then a standard size one, then finally a micro SD card all of that becomes unique magic. You can talk about the fact that even though the technology gets smaller and smaller somehow the amount of stuff you can save on the card remain the same. Or even gets bigger.

The philosophical implication of the card being so small it is practically gone and what it means about the value of storage and data really should get an interesting plot going.

Or think toys. A toy car shrinking more and more. Suitable props should be cheap.

All I'm saying that the plot of an object shrinking really is intriguing as it flies off in so many directions.