Crosis, the Purger [Commander 2017]

Set: Commander 2017 Type: Legendary Creature — Dragon Rarity: Rare Cost: {3}{U}{B}{R} FlyingWhenever Crosis, the Purger deals combat damage to a player, you may pay {2}{B}. If you do, choose a color, then that player reveals their hand and discards all cards of that color.