Stormbreath Dragon

Protection from white is the part that did the work, and it pays for itself in specifics. It dodges white's targeted removal and lets the dragon punch through white blockers, while leaving it just as exposed to a sweeper as anything else: Wrath of God still destroys it, because that effect neither targets nor deals damage, so protection has nothing to catch. What it shreds is the white spot-removal plan, the Path to Exile and Banishing Light answers that hold the air, plus the white wall meant to stall it on the ground. Haste meant the clock started the turn it landed, and flying meant it kept ticking against decks built to trade on the ground.

The monstrosity payoff turns a stubborn beater into a reach finisher, and the activation is an instant-speed ability, which is the real wrinkle. The cost is steep, but you can hold the mana and fire it during the opponent's turn, or in response to a removal attempt, rather than tapping out on your own. When it becomes monstrous, the trigger burns each opponent for their full hand size, punishing exactly the card-hoarding, draw-go control deck the protection clause was already harassing. Against a topdeck war the burn does little; against a hand full of held-up counterspells it can close the game outright. Two independent angles of attack, both aimed at the same archetype: a dragon engineered as a control-killer.