Box in a Box
At a first glance, this strange object appears as a common, Diminutive wooden box. However, its incredibly complex hinges, lids and locks allow it to close in such a way as to be contained within itself. Physically impossible by the prime material’s natural laws, this effect allows the box to exist inside itself when closed, which makes it effectively nonexistent. Any objects carried inside the box become nonexistent as well, making the box in a box what may be the safest way to carry one’s valuables in all the known planes. A box in a box comes with a special key, which may be used to lock or unlock the box at any time.