Lol, I didn't notice the Graboid. >.<" But yeah, I agree with you about running two TU's instead of Bone Walls, but I still stand by the golem. There's only one creature that requires Earth, and it's a cheap creature. With that number of Supernovas, I think that a Lava Golem would be a much better choice, since even though it starts out with much more attack and much less hp, both grow over time, unlike the spectre, which is much more vulnerable to Otys anywhere in the game. But I guess, like I said before, it's all up to personal preference, and ultimately the luck of the draw and your opponent's deck decide how effective it is at any given time.