Got the Monoprice Mini, it's a great printer. Looking on here for things related to it and I found a bunch of different spinner designs that fit on the end of the extruder gear shaft. Looked at them and none jumped out at me until the cartoon hand spinner, which I was about to print until I thought of the classic Rude Gnome design. A little bit of (admittedly rushed and sloppy) work in MeshMixer and we've got the Rude Gnome hand transplanted onto the base of the cartoon hand spinner.
See it in action: https://youtu.be/OkhihAvl9zQ - it's particularly funny when the printer is doing detail work at the end and is retracting and extruding rapidly.
Update! Just so happens that the inner diameter is an almost exact match for Lego mini figures, which as you can see from the last photo results in some really funny stuff.
I printed with supports because I was lazy and did a crap job of lining up the hand with the round base. They broke off easy, and honestly probably weren't even necessary. The fit on the motor shaft is kinda loose, not sure the keyed part actually does anything, but the hand spins, so I didn't do too much more with it.