I agree with most of what's been said. Looks like a really fun card, but the cost and attack make it too powerful. If you tweak those, I think you'll have a great card on your hands. Halving the initial attack to 3 and 4, for instance, feels about right to me just on gut reaction. Even if it had no ability, for instance, it's almost as good as lava golem/destroyer, and that card is borderline OP with its cost/attack ratio.
The best combo I see with it isn't stoneskin or SoD, though; it's shard of sacrifice :p