Seed Spark
The structure works without a kicker mechanic anywhere in sight: the green is folded into the base cost, not added to it, so spending for one of the three generic mana flips on the rider rather than paying a surcharge. A pure white caster pays four and gets a clean answer to any artifact or enchantment, no worse off than if the splash payoff never existed; a Selesnya pilot routes that same generic pip through a green source and walks away with two Saprolings on top of the kill. The two-mana naturalize effects have existed since the earliest days, so the four-mana floor here is a deliberate tax, the cost of bundling the go-wide bonus into the same instant instead of asking you to find it on a separate card. What lifts it above that tax is the body it leaves behind: a reactive spell that normally trades one-for-one becomes a one-card net positive, killing a permanent while building toward a token army. This is the two-colors-in-one-instant build a guild-block set leans on to make a green-white splash feel earned, the optional-mana clause doing the work that a true splash payoff card would otherwise need a whole second slot to provide.

