Mami's Soul Gem

thingiverse

Own a Mami-like "mahou shoujo" soul gem from Puella Magi Madoka Magica by forming a contract with Kyubey! Be prepared, though, as this choice may lead to your transformation into a witch. To create your own soul gem, simply print both sides and glue them together using the adhesive of your choice. Don't forget to personalize it with paint. Alternatively, you can also try printing an unprintable one - I've heard it's possible!