That art is making me hungry... it looks like a giant cookie! mmmm cookies...
The card looks cool, too, but having a pumpable momentum/shrouded creature is awfully powerful, even if it is in two elements. I mean, once it got both, NOTHING could kill it. With immaterial, the only things that can kill it are shields, and with momentum, shield's can't kill it, so it's literally invincible after a couple turns, unless it got poisoned beforehand. Instead of both momentum and immaterial, I think it should only get one of them, and maybe get something else in place of them. Adrenaline and vampiric don't make sense on a rock; not sure what else there is to give it, though. If you were to take one away, I'd take away immaterial. The momentum makes more sense on a rock than immaterial.