Alabaster Potion

White's two oldest defensive jobs, lifegain and damage prevention, packed into one modal instant with an X dial bolted on. The split matters more than it looks: the lifegain mode is a race-tightener and a way to blank a burn spell at instant speed, while the prevention mode does triple duty as a combat trick, a burn shield, and a targeted bodyguard. The any-target prevention clause is the more interesting half by modern standards, since one card can save a creature mid-combat, soak a direct-damage finisher pointed at its controller, or shield a planeswalker from a swing that would otherwise resolve unblocked. The double-white in the cost keeps the rate honest: this is not a splashable insurance policy, it is a commitment to a white-heavy mana base in exchange for arbitrary scaling. The era that produced it was full of cards that asked players to pay X for effects the design team was still struggling to price tightly, and this one lands on the more reasonable end of that experiment: the floor is genuinely low (a two-mana cast does almost nothing), but the ceiling scales linearly with available mana in a color that has always struggled to turn surplus late-game mana into impact. The lineage runs straight from here to the modal X-cost instants white would spend decades refining, a primitive but recognizable ancestor of the form.