maybe put a turn count on reducing attack? say, reduce attack for 2 turns, to prevent locking down the opponent? I get the original idea of the card, siphoning life (attack) from a creature in order to create a shade, but it just seems too powerful to have both abilities come not only from the same card, but the same ability. IMO permanently reducing attack is something that should not come with a benefit for yourself. It is a very powerful ability, not yet reversible (most likely because its not implemented), and so needs a detriment instead of a benefit. High cost, reversibility, etc. Possibly make it go away over turns, suck 2 attack, they regain 1 per turn?