The back dorsal plates were cut out from black stiff foam

The back dorsal plates were cut out from black stiff foam. I used a box cutter with one of those blades where you can break off pieces of the blade so you always have a sharp tip. With the blade fully extended if gave me about 4” of razor sharp edge to sculpt the foam. I found images of a Godzilla model kit that had all the back dorsal plates laid out next to each other and used that for reference to shape the dorsal plates.