Stet, Draconic Proofreader

Flying
Whenever Stet, Draconic Proofreader attacks, you may exile a card from your graveyard. When you do, Stet, Draconic Proofreader 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.