Angel of Grace

The enters trigger is the whole reason this 5/4 flier is priced the way it is, and the mechanism is more precise than a fog: the damage still lands and still resolves, but for the rest of the turn, any hit that would drop your life below 1 instead leaves you sitting at exactly 1. It does not prevent damage, it does not promise you can't lose, and it does not stop an opponent from winning by other means: it just floors your life total for a single turn. Cast at flash speed on the opponent's turn, that converts an alpha strike, a lethal burn spell, or a lethal combo into a survived turn plus a flying body that blocks and swings next turn. The flash is what keeps the answer from telegraphing itself; you hold up the five mana and let the opponent commit to a lethal that no longer is. The graveyard ability is the second life the card was designed with, a way to matter after it has traded or been killed: exile it from the yard to set your life total to a flat 10. That is a hard reset when you have been ground low and a genuine loss when you haven't, so the number cuts both ways depending on the game state. Everything about the rate only pencils out because the survival lasts exactly one turn, not because the body is oversized.