Nick Fury, Spymaster

White aggro is built around the wide swing: go tall on tokens, punish blocks, attack with everything at once. This card rewards the opposite discipline. Its trigger fires only when a single creature attacks alone, the one attack pattern white boards almost never want to make, and pays that lone swing with a card plus a free deployment. The body it drops in is not just extra presence: it enters tapped and attacking, joining a combat already declared, and comes with indestructible for the turn, so the sweep or trick that would normally answer a solo attacker whiffs. The timing wrinkle matters. Because the creature is placed straight into the attack rather than declared as an attacker, "whenever this attacks" clauses never see a declare-attackers step and stay silent, so the free body is a clean beater, not an on-attack engine. The mana-value cap of three or less walls off haymakers, but that is a wide net in white: mana dorks, hatebears, sacrifice fodder for aristocrat lines all qualify. The strategic axis is where it turns genuinely strange. A deck built around this wants restraint, holding creatures back so one can go in alone and multiply, an unusual thing to ask of a white board. First strike on the 4/4 is the incidental sweetener; the real work is converting the lone-attacker line, normally the sign your board has run dry, into a draw-and-deploy engine.