Cig Neutron is a freelance sculptor and special makeup fx artist. He did some awesome Nintendo Sculpture for The 3NES Show. He did a Kraid, Darunia, and Wario Busts.
He also worked on a Bowser and a Motherbrain sculpture!
Here is a video of him making Motherbrain!
Go and check more of his work on his page and DeviantArt!
Sources, 1, 2, 3