Yeah I agree with Higurashi, this card seems a bit UP to me. Throw it up to 50% or decrease the cost by 1 for each and it'd be useful. I'd probably go with the 50% buff seeing as its a crisper number to work with, lotsa cards have an even attack number.
This card might work nicely in a Fire golem deck, other than that I don't see it being more useful than a Steel Golem or an Elite Graboid (same or similar costs, better change in damage/turn). Though, when used multiple times on one creature, you get some serious damage improvements.