Cultivator Colossus

The enter-the-battlefield trigger is the whole engine, and it is built to feed itself. Each land you put onto the battlefield draws a card, and every card drawn is another chance to find another land, so the moment this resolves with a handful of lands you have a self-fueling chain: land, draw, land, draw, until you run out of lands or run out of hand. Note the mechanical trick that makes it so strong: the trigger puts each land directly onto the battlefield rather than playing it, which sidesteps the one-land-per-turn rule and the sorcery-speed timing that would otherwise cap the process. A creature whose stats scale with your land count is an old green idea; what separates this one is that it manufactures the very lands that grow it while replacing itself many times over. The "you may" and "if you do" are the safety valve: nothing compels you to keep going, and drawing off an empty land hand simply stops the loop rather than decking you. Green rarely draws cards in bulk without paying for it, and this hides the draw inside ramp, so the engine reads as fair even as it refills your hand and thins your library. Because the whole trigger resolves at once, there is no priority window to interrupt it mid-chain; the guaranteed loops instead lean on a top-of-library replacement effect like Abundance, converting every draw into a land so the chain never whiffs. The trample and swelling body are the finisher bolted onto what is, underneath, one of green's most explosive card-advantage engines wearing a ramp payoff's clothes.