So anyway, keep in mind I was trying to do this as cheaply as possible, and some of this is shortcuts: I bought a half-cast plastic taxidermy mount online, and epoxied it to a stack of boards I cut and glued together to fit the mount. I ran HVAC metal tape around the edges of the boards to hide the wood grain. Then I used drywall joint compound to hide the edges of the tape, create the texture of the carbonite, and merge the mount into the background, with a few splotches on the mount itself. When the drywall mud was dry, I gave it a coat of Triple-Thick Varathane. Then I sprayed several coats of metallic silver paint on it, letting them dry and cure in turn. Finally I did a partial coat with a black metallic paint - like oil rubbed bronze, or something like that. As soon as I got that coat on, I went back with a paper towel damp with mineral spirits and buffed away the dark paint to make the texture pop. The mineral spirits doesn't cut through paint that's already cured if I'm careful, so taking back the dark paint just shows the silver underneath. I deliberately went a little too hard on the outside edges, so the metal tape started to show through. Voila!