Covert Demonic Dragon, Mandala Lord

/:If you have a non-Murakumo vanguard or rear-guard, this unit gets -2000. :[ 1 & Choose a card named Covert Demonic Dragon, Mandala Lord from your hand, and discard it] At the beginning of the guard step of the battle that this unit is attacked, you may pay the cost. If you do, choose one of your opponent's attacking units, and that unit gets -10000 until end of that battle.