Howl from Beyond

The X-pump as a finisher template. Alpha printed several variable-cost combat tricks, one per color, and the black version is the one whose math gets ugly fastest: every point of X is a point of power, with no toughness, no trample, no second clause to balance the rate. The design logic is that black pays full price (no kicker mode, no graveyard rider) and gets the cleanest possible scaling in return: power that climbs as deep as your pool will pay for, with only the base black pip as overhead. The absent toughness is what disciplines the rate. A blocker that survives the swing kills the attacker on the way back, so the spell wants an unblocked creature or a trample enabler; it is a kill spell aimed at the opponent's life total, not a combat-survival tool. That framing files it with Banefire and trample-enabler effects rather than the Giant Growth family, even though the text reads like a pump spell. Casting it as an instant completes the equation: held up as a bluff, it punishes the opponent for tapping out or leaving the wrong blocker back, and it lets you wait until blocks are declared before committing the mana. A simple card, but the shape it established (mana spent becomes power, delivered through a creature, resolved before the turn ends) has been re-explored in every era since.