Stet, Draconic Proofreader is a rare Legendary Creature — Dragon Bureaucrat card from Unsanctioned (UND), collector number 57. Current market price: $0.21, TCGplayer market prices via Scryfall.
Flying Whenever Stet attacks, you may exile a card from your graveyard. When you do, Stet deals 4 damage to any target whose name begins with the same letter as the exiled card. {W}: Delete the first letter of target permanent or player's name until end of turn.