Sulfur Falls

The check land template solves a problem the original dual lands and shocklands handle differently: it wants to enter untapped without costing you life and without demanding you crack a fetch. The condition is the elegant part. Rather than counting lands you control by raw number, it asks whether you already hold a land carrying one of its two colors' core types (an Island or a Mountain), which means it gets better the more of those types you run and worse in a vacuum. Any land bearing those subtypes flips it on, so a manabase of shocklands, surveil lands, or even other typed nonbasics will satisfy it just as readily as basics will. Early in a game with a relevant land already down, it is a painless dual; later, in a flood of these and not enough Islands or Mountains, it stumbles in tapped. That self-correcting tension is what keeps the cycle honest, and is why these reward a manabase intentionally weighted toward typed lands rather than colorless utility or off-type duals. As the Izzet fixer specifically, it underwrites the spell-heavy, tempo-sensitive decks that least want to drop a turn or pay life for color: exactly the strain of deck where entering tapped hurts most and where the type check is most often met. The design has aged into a default, a low-friction dual whose only cost is the discipline of building around the lands it asks you to already own.