You and your friend John both enjoy Magic the Gathering, but you've gotten into an argument over which creature is the best. The two of you agree that the only fair way to settle this is to see how good each creature is individually. You proceed to build decks consisting of 59 basic lands and the one creature under consideration, and see how quickly you can kill an opponent whose deck consists of 60 basic lands.
The best creature according to the two of you is the one that can win this arrangement on the earliest turn possible (and, as tiebreaker, deal the most damage to the opponent). You may stack your hand and deck however you like at the start of the game.
After investigating all creatures legal in Vintage, which do you and John conclude is the best?
Example: A deck consisting of Brushstrider and 59 basic forests can deal 21 damage by turn nine.