I was wondering if an object that changes its own mass could exist. But let's try not to fill it up with air or other gas so it feels "lighter".
That way you could protect things from being stolen if the weight increased A LOT, removing usability from it.
- You could apply that to a bike or a scooter being way heavier and really hard to navigate (and you would need something like a key to switch between the two states Heavy/Light).
- You could use this to do a magic trick with like a Thor hammer being super heavy and all of the sudden you change it's mass and tell a random guy to pick it up and it would be possible for him since it's now a bearable weight like a few kg when it was impossible to lift it up more than a few cm before because it's really heavy, but not insanely heavy since it's not that big. (Or maybe it would indeed be insanely heavy thanks to your solution.)
Would this be possible?
First, something that changes its own mass.
Then, a change that is significant enough to feel.
And, finally, if not possible by itself, maybe some external ways (not too obvious for people around the object) to change mass (both ways) that could be used for the Thor hammer trick because this would be so awesome.