So basically a creature that has a 'spreadable' (Growth) ability?
I already know that
has Momentum, so this card does seem a bit much. Perhaps you should raise the ability cost first (or change it to a different element) and see where that takes you, while reducing the attack slightly to say 2-3 attack (if it can use Forge on itself, then basically you have a Growth creature that has massive HP and is purely mono, unlike Lava Destroyer and Forest Specter).
For the table, please do the following:
-WRITE OUT your card's ability in the table word for word. "Forge" isn't sufficient.
("
Forge: the target
creature gains +2/+2.")