Crash the Ramparts

Green's pump baseline with a rider that changes the target math: +3/+3 alone only ever matters at the point of combat, but trample converts a chump block into damage that gets through, which is the whole justification for reaching past a plainer growth spell. Set it against Giant Growth, which hands out the same +3/+3 for a single green mana, and the extra two mana is buying exactly one thing: the trample. That is the trade green keeps offering at common. Pay more, and the effect stops being contingent on a favorable block and starts closing games through a wall. Built as ceiling fodder for creature decks that want their large threats to end the game in one attack step, where trample on something already sizable turns a stalled board into a lethal swing. There is no decision space past when to cast it, and a common combat trick is not asking for any: it does its one job cleanly, no build-around required.