Maester Cressen

{g}{g}, {t}: Target creature you control gains +0/+2 until end of turn.

Pay two life, Sacrifice Maester Cressen: Flip a coin,
if you win the toss destroy target creature an opponent controls.

“He was a maester, trained and chained in the great Citadel of Oldtown. What had he come to, when superstition filled his head as if he were an ignorant fieldhand?”