Three possible head designs, and four spine designs. You can probably see bits and pieces of various incarnations among them.
Because Godzilla is, to quote Tomoyuki Tanaka (one of the creators of the franchise), “the sacred beast of the apocalypse”, I tried to make him suitably twisted, unnatural-looking, and more than a little sinister.
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SliferFox
I think a combination of A and B, and 1 and 3 would look interesting o: