Sakiko, Mother of Summer

Combat damage becomes a mana battery, and the design wrinkle is that the mana refuses to empty between phases the way it normally would. Mana from most sources evaporates as steps and phases end, which is why you cannot float green during combat and spend it postcombat without a card that says otherwise; this Snake Shaman says otherwise. Connect with a swing and you convert that damage into a pool of green you carry into your second main phase, ready for a fat creature, a big X spell, or a chain of activations the rest of your hand could never otherwise afford. The conversion rate scales with the board, not the body: the 3/3 here is a delivery system, not the payoff, and the more attackers (or the more trample on a single fattie) the larger the surge of mana once combat resolves. That ties the card's power directly to whether your green deck is built to land damage in the first place, which is the discipline the effect demands: a token swarm, an evasive beater, or a Voltron threat all turn this into an explosive ramp turn, while a defensive shell leaves the trigger inert. It belongs to green's small lineage of attack-into-mana engines, cards that ask you to deal damage and then reinvest it the same turn rather than ramp through lands, and it remains one of the most aggressive interpretations of that idea.