Okay, I'll buy that this thing is called Marshadow. But there's one thing that still doesn't make sense to me: the Mars connection. Mars doesn't fit with the sun/moon theme, and it doesn't have a lot to do with shadows at all.

So I propose a different hypothesis. Just look at the fiery red eyes. Note the smoke coming off the top of its head. It doesn't look like any kind of Mars thing, but it does look an awful lot like a roasted marshmallow.

Calling it now: Marshadow really is a marshmallow.