What is Ghost about this thing? The glowing energy inside it? Yellow means Electric, purple means Ghost, everyone knows that.
It's not a spirit that lives in a statue, because nothing in its pokédex entry alludes to it being undead or possessed in any way. It was supposedly made by ancient *science*, not magic.
Correct me if I'm mistaken, but I don't think the original golem myth said it was powered by a human soul, so that's no excuse.
A Ground/Ghost pokémon would be a skeleton.