Seal Away

The "tapped creature" clause is the whole hinge, and it marks a real departure from the white removal enchantments that came before. Oblivion Ring and Banishing Light pay full freight to exile anything, no questions asked; this one shaves a mana off the rate in exchange for a genuine condition. Because it is not an Aura, the spell itself has no target: it resolves into an enchantment, and only then does the enters-the-battlefield trigger pick a tapped creature an opponent controls, with that legality checked again when the trigger resolves. Flash turns the tapped restriction from a downside into a trap. You hold up the mana, let the attacker swing or the mana dork tap for value, and answer it at instant speed once the creature has already committed. The flash window does double duty: it ambushes an attacker mid-combat, and it sidesteps sorcery-speed counterplay by deploying after the opponent has tapped down. The exile is temporary, tied to the enchantment's presence, so it carries the same vulnerability as every "until this leaves" effect: destroy the enchantment and the creature comes home. That is the price for the discount and the flexibility. The card ends up playing like removal disguised as enchantment-removal bait, an answer for the deck that keeps its mana open and would rather punish the act of attacking than the mere existence of a creature.