As a robot with a soul, Mettaton starts out in Undertale as a gray box. Then he evolves into Mettaton EX. The humanized version is the one Katelyn Jones Cosplay went with. She replicated the character’s metallic looking makeup with body paint and a silver stretchy fabric. Katelyn crafted the spandex suit and embellishments. The armor pieces started as EVA foam that Katelyn fitted onto a duct tape mannequin. You can see a couple of making-of photos below.