Fishliver Oil

Islandwalk's earliest commitment to being a real mechanic rather than a flavor curiosity. The design is almost embarrassingly literal: smear a fish on a creature, and it slips past anyone defending an Island. That literalism is the point. Evasion auras at two mana are a tricky design problem because the card-disadvantage of Aura plus creature has to be paid for by an unblockable clock, and the early-Magic answer was to gate that clock on an opponent's land type rather than a global drawback. So the card swings violently with the matchup, from useless against red and green to a reliable unblockable threat against another blue mage. The conditionality is the lever: a clock the opponent can never interact with in combat, but only when their manabase cooperates. That same conditionality is the seed of an entire support package built later to make islandwalk pay off on demand: land-type changers like Spreading Seas and Phantasmal Terrain exist precisely to manufacture the Island that Fishliver Oil's evasion depends on, turning a matchup-dependent gamble into a setup the caster controls. The Arabian Nights solution was to leave that dependency raw and trust the format to be blue-heavy enough to matter. It mostly was. The flavor (a glistening bottle of oil that makes you slick enough to swim past sentries) also ranks among the cleaner mechanical-to-flavor mappings of the era, back when a card's name was expected to do half the rules-text's explanatory work.