Urza's Ruinous Blast
Exile every nonland permanent that isn't a named thing, and let your own board of legends walk away clean: that is the promise, and the gate on the front is what makes it fair. You cannot even propose this sweep unless you already control a legend, which means the effect is priced not in mana but in deckbuilding commitment. Stack the battlefield with commanders, legendary creatures, and planeswalkers, and the wrath becomes a one-sided judgment by construction; run a board of generic beaters and the spell never unlocks at all. Exile, not destruction, is the axis that separates this from a conventional board wipe: regeneration is irrelevant, death triggers never fire, and recursion finds an empty graveyard. The restriction is checked only as you cast it, so an opponent who kills your last legend in response does not counter the spell or claw anything back; the sweep still lands. What the design punishes is the wide, undifferentiated battlefield, and what it rewards is the curated, top-heavy one, structurally rather than as a happy accident.
