Wave Elemental

A pseudo-Fog stapled to a body, with a discount: instead of stopping all combat damage for a turn, it taps up to three nonflying creatures before they can attack (or block) and walks off the table. The sacrifice clause is what defines it. This is a one-shot tempo play that wants to be cashed in at the moment of maximum leverage, not a repeatable engine, and the design pays for the flexibility of choosing your targets by demanding the creature itself. The flying restriction is the other governor: against a ground-based aggressor it can blank an entire attack step, but it offers nothing against the air, which keeps it honest in a color that already polices the skies through other means. Played defensively it neutralizes a swing; played offensively, tapping down blockers before declaring attackers, it functions as a small board-clearing alpha-strike enabler. Either way the activation costs an additional blue mana on top of the tap, so the window is narrow and the timing deliberate: you hold it up, read the combat, and spend the whole card on the swing that matters most. A representative piece of mid-90s blue: a creature whose stats are almost beside the point, valued entirely for the instant-speed combat trick locked inside it.