Crosis, the Purger is a rare Legendary Creature — Dragon card from Commander 2017 (C17), collector number 168. Current market price: $0.63, TCGplayer market prices via Scryfall.
Flying Whenever Crosis 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.