I found a picture of a plutonium “pellet” that NASA uses to power everything from the Voyager spacecraft to Mars rovers. I find these little radioactive marshmallows beautiful and fascinating - and I wanted my own. I researched the actual size and built one, complete with a NASA storage container. 

The pellet was built in Fusion360, printed on my Mars Pro 3D printer, molded, and cast in red-tinted resin. The canister is scrap plumping bits from the shop. Pretty much a one-day build with stuff I had sitting around.