Fortify

The modal split is the whole design idea here: a team pump that lets you choose, at the moment of declaration, whether you are pushing damage through or surviving the swing back. Most mass combat tricks of this kind committed to one direction, but the choice between +2/+0 and +0/+2 means the same card can finish a race or blank a board-wide block depending on which way the math is breaking. The instant speed is what makes the choice live: held up through combat, it punishes an opponent who attacks or blocks on the assumption your creatures are the size they appear, and the decision waits until after they have committed. The cost keeps it honest, since three mana for a one-shot anthem only pays off when you have a wide board to multiply across, which ties the card squarely to a go-wide token or weenie shell rather than any midrange use. As fixed effects go it is a modest one, a sweetener for a deck that already wins through numbers, but the design instinct it represents (giving the pump spell a defensive mode so it is never a dead card against a fast clock) is the reason this kind of split-mode trick keeps reappearing for white aggro.