Tempest Djinn

The triple-blue cost is the whole transaction here: it demands a deck so committed to Islands that the printed 0/4 body is a downpayment, not a final number. Every basic Island swings it upward, so in a dedicated mono-blue shell it lands as a flier that hits for three or four and only grows as the manabase comes online. The design ties the payoff directly to the deckbuilding restriction, which is rarer for blue than for white-weenie or red-aggro count-your-permanents creatures: blue's beaters historically came with evasion and a soft body, and the color was nudged toward control rather than the board. What makes this one notable is that it punishes nonbasic greed without an activated cost or upkeep tax. The only thing keeping it honest is the word "basic," which quietly excludes the dual lands and utility nonbasics that aggressive blue decks would otherwise want, forcing a flat, color-pure manabase if you want the body to matter. A flier with four toughness also sits above most early-game removal that scales with power, and it blocks ground attackers indefinitely while clocking through the air, so the asymmetry between its defensive toughness and offensive power is the point. It is a mono-blue aggro enabler in a color that rarely gets one, and the requirement is both the cost and the identity.