recently I have been playing many growth creatures in my deck. Many times, they get to 20 attack and get antimattered.
Can I re-antimatter the creature with negative attack to get positive attack again? I'd like to know because then I wouldn't have to spend another 10 turns trying to grow creatures back up to 0 attack. Also, I haven't used antimatter enough to have actually upgraded it and put it in my deck. I'd like to know whether I should upgrade one and put it into my deck.