MArcomage

I would say, that this Card is too weak. Most time the discarding of a common Card is for the enemy a win insted of a loss. It will be even worse if the enemy gain a uncommon. I would say that the Card will be replaed by another common from his deck or one which is not in his deck.

well, this card can be very helpful. e.g. in a tower destruction deck is good to discard lookout towers. or in a titan deck to discard tribute. or simply to break a combo like nature or restoration ones.and it's common so it's easy to find a place for it in your deck. finally it's illusion so you can get a rare if played after a non common illusion. I think that this card is already good, maybe I should lower the cost a bit, but nothing more. anyway it's good also the idea of replacing the enemy card with a common

I could swear there was already a topic for this concept...

Anyways, I agree with Filthz, I think it's an excellent idea, and pretty decently balanced. I guess you could make it 1 gem instead of 3, and I don't think anyone would complain.