Summer Bloom

A spell that uncaps the one-land-per-turn rule, and does nothing else: it adds no mana, draws no cards, and demands you already have the lands stockpiled to cash in. That requirement is the whole design. The structural trick is that it converts a resource most decks ration (one land drop per turn) into a tap you can open all at once, collapsing several turns of development into a single sorcery-speed window. On its own that is a build-around curiosity. Paired with cards that untap or recycle those lands, the acceleration stops being linear, and that is the line designers have eyed nervously for decades, because lifting the land-drop ceiling scales past its printing rather than with it. The card is only powerful in a shell specifically configured to abuse the sudden flood of mana, which is why it became the glue of fast ramp-into-payoff strategies rather than a generically useful spell. The same property has made it a recurring subject of bans wherever a critical mass of untap effects and cheap payoffs assembled around it: the printing looks innocuous, but it uncaps a rule the format is otherwise balanced around.