Pestilence, Prince of Plagues (Monochrome)

20: When a Clash card an opponent controls is defeated during a Primary Phase, you may engage this card. If you do, draw one card. 12: Once per turn, during your Primary Phase, you may discard one or more cards from your hand. If you do, target Clash card gets -X/-X until end of turn, where X is equal to the number of cards discarded this way plus one.