Crucible of Worlds

Lands are the one resource the game refuses to let you recur by default: every other card type has its graveyard answers, but a fetched, sacrificed, or destroyed land was simply gone. This single static ability rewrites that rule, and it asks nothing in return: no mana sink, no activation, no upkeep tax. It just sits there making lands behave like every other permanent. The consequences run in two directions. Defensively, it blunts an entire category of attrition: land destruction stops being permanent, since a Stone Rain or a Wasteland blast can be replayed next turn, and a fetchland stops costing a card to crack because it comes back to be sacrificed again. Offensively, any sacrifice-a-land effect becomes an engine; Zuran Orb or Constant Mists fed by a single land each turn turns the artifact from a quiet enabler into a grind machine. That permissiveness is exactly why it has spent its life on a knife's edge of power level. Pair it with your own repeatable land destruction (Strip Mine or Wasteland, recurred each turn) and the symmetry tips into a one-sided lock: you blow up an opponent's land every turn while replaying your own, and they cannot keep up. The design lesson it taught is that recursion of the one card type nobody had bothered to protect is far more dangerous than it looks on paper, and most repeatable land-sacrifice effects printed since have been costed with this artifact's existence in mind.