Mage Duel

Green fight spells have always been priced on the assumption that the fight itself is the whole payment: your creature has to be big enough to survive, and you eat damage as the cost of removal. This one changes the ledger by tying its rate to a spellcasting condition. Pay full price and it is a modest pump-and-fight at sorcery speed; cast another instant or sorcery earlier in the turn and it drops to a single green, turning removal into a spell you can afford to fire off casually rather than agonize over. The +1/+2 rider is doing quiet structural work in that math: the extra toughness is what lets your creature win a fight it would otherwise trade in, so the discount and the buff both point at the same play pattern. Because the reduction only counts a spell you have already resolved (or at least cast) this turn, its natural home is the spells-matter shell rather than the stompy one: a curious place for a mechanic green has traditionally used to punish opponents with fewer creatures on the board. The cost reduction is the design's real content; the fight is the familiar frame it hangs on.