What happens if Mewtwo EX uses its "Damage Change" attack against a Pokemon that blocks effects of attacks? Does nothing happen, or does Mewtwo EX get to remove its damage counters?
Mewtwo-EX would remove its damage counters, but the opponent's Active Pokemon would not remove nor receive any. If you try to move damage *to* something that blocks effects, the damage disappears. If you try to move damage *from* something that blocks effects, the damage stays there.
Damage Change