Bobble the head of your favorite tyrannical leader of the evil Decepticons!
I got the Megatron head model from this set of parts on Thingiverse:
https://www.thingiverse.com/thing:2373072/files
All I did was scale it appropriately, and use the template negative volume to cut out the hole. Get the rest of the needed parts (spring and base) from the linked original Bobblehead models, or use my 3MF file or print the provided gcode appropriate for your printer.
Transformers! More than meets the eye!
The author remixed this model.