The crystals in the Superman films had several functions: home construction, beacon, glow stick, ability to restore superpowers, and last but not least: data storage. Two of these things — data storage and the glow functionality — could easily translate to a USB flash drive. The end result is something that looks and behaves (to an extent) just like one of Superman’s crystals.
For this design a vanilla cap would cover the USB plug. Like the previous Ghostbusters design, there would be some LED lights built-in to indicate the device is in use. But one thing I’d like to see is an on-demand light that is triggered by a button, allowing you to replicate the ‘glow stick’ feature of the crystal. The drive would need an on-board battery, preferably something that can be recharged (via USB, of course). There are so many keychain light and USB drive combos, so I feel this is an attainable design.
And as a lark it should come preloaded with a few documents about trees.