Black Panther, Claws of Bast
The counter clause reads like a payoff for a build-around, but the condition is doing all the strategic work: your creature only grows when it attacks alone, which means the reward is fundamentally in tension with going wide. This is a Voltron incentive dressed as an aggro one. You are asked to commit to a single threat, swing it in unaccompanied, and let it compound across turns, each attack stacking another counter and each point of combat damage feeding back as life through the lifelink. That loop is self-reinforcing in a way that punishes chump blocks: the more they let it through, the bigger and the more insulated (via lifegain) the attack becomes, and the more it dares them to trade a creature they cannot spare. The elegance is that the two lines of text point at the same play pattern. Lifelink stabilizes the solo-attacker plan against the aggression it invites, and the counter rewards the discipline of not diluting the swing. As a three-mana white body, it sits early enough to start the escalation before the board fills up, which is when the "attacks alone" clause is easiest to satisfy honestly rather than by attrition. What holds the design in check is that same word "alone": the moment you deploy a second attacker the engine stalls, so every counter is bought with the opportunity cost of a wider board.
