Shrödinger's Cat Toy
For those that are unaware, Schrödinger's cat is a seemingly paradoxical theoretical experiment devised by Erwin Schrödinger. The experiment proposes that a cat be placed in a sealed box. Within the box is a device that will kill the cat (such as a canister of poison gas) which is attached to a trigger that will operate randomly with a 50% chance of going off in an hour. According to quantum theory at the end of the hour the cat is both alive and dead until the box is opened and the result observed. Thus the observer becomes an integral part of the experiment.
The simplicity of the Cat Toy lies in its collectability. Ninety nine out of one hundred Shroedinger's Cat Toy boxes are empty. Only the hundredth contains the actual toy. But the packaging is constructed so that it is impossible to tell the difference between the one containing the actual toy and one without, as they are exactly the same in size and weight. The packaging is also constructed so that the only way to open the box to find out whether it contains the toy will destroy the packaging beyond repair.
Thus it is impossible to ever know whether you have the ultra-rare real Cat Toy without opening the box. If you open the box it is no longer in collectable condition, regardless of whether it contains the toy or not. And so according to Schrödinger's theory this therefore means that every box simultaneously contains the toy and doesn't contain the toy.
It's a quantum collectable. It'll drive collectors insane...