Groundswell

The conditional pump that turned a sequencing habit into a payoff. For a single green mana you get the floor of a fine combat trick, but the upside is gated behind something most green decks do every turn anyway: dropping a land. The mechanic's elegance is that it asks nothing extra of the deck, only that you hold the spell until after the land hits, and the reward for that small discipline is a swing that can flip a block, push a near-lethal attack over the line, or save a creature against burn the opponent expected to be enough. The numbers do the persuading: the difference between a modest boost and a game-ending one is whether you bothered to play your land before passing priority, which makes it a clean teaching tool for why land sequencing matters. It sits in a lineage of one-mana green tricks that price aggressively while building in a condition that separates the engaged pilot from the autopilot, and the landfall condition is doing the work that an additional cost or a tapped-creature clause does on other pump spells: it caps the ceiling unless you earn it. Cheap enough to play on curve, swingy enough to matter at instant speed, and entirely free if your deck was going to make a land drop regardless.