Use that four mana kill something and destroy a mana crystal spell. Yes it sucks, but they are overloaded next turn so it's not as bad as it would otherwise be. I play combo druid and I use naturalize. If it comes out early and u have to give them two cards, yeah it sucks, but you can stay alive and try to recover. if it comes out late, naturalize can mill so key cards for them. The warlock spell has similar downside early, but upside later aspect. Also the doll plus defile works pretty well.