Apparently it was made using a 3D printer, so it's made of a material like corn starch with bonding "glue" mixed into it. EDIT: 3D printers are used in the design industry for "rapid prototyping." That means you can print a functioning test part in a matter of hours instead of waiting days or weeks for a plastic or metal casting. The part's weaker, but it's good for testing fit and light function. A test part can be used to make the final casting mold, too. But, of course, they can also be used to make random fun things... :P
I think he'll probably be selling those on that Madoka event that's coming up. He generally sell his statues in doujin conventions like Reitaisai, Vocafes and Wonfes.