High on the list of challenges was designing a "thing" that would land upright and be capable of being grabbed by a claw. Once I started, several things were created.
Two particular creatures took on a Halloween mode.
Full details can be found here, and the print files are included on this site.
The less attractive, but more workable (for the moment--who knows what I'll end up with) "thing" starts with a few 3d printed pieces and four US nickels.
Place the nickels in the bottom piece (printed at 85% scale and 100% fill).
Add the plug (printed at 100% fill).
Take the long rod (printed at 10% fill on a raft) and place it inside the rings (printed at 10% fill). Melt the rod to the rings using a soldering iron (or glue with superglue).
Melt (or glue) the top to the bottom.
This "thing" will always land rod side up.