Stet, Draconic Proofreader (Unsanctioned)

Legendary Creature — Dragon Bureaucrat - 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.