Sweep Away

A bounce spell with a defensive reward folded into the resolution. The base mode is the familiar Unsummon-plus-tax rate: three mana to send any creature back to hand, a tempo play that buys a turn against a threat you cannot kill outright. The conditional clause is what lifts it past overpriced removal. Cast it on an attacker and the spell checks the creature's status as it resolves; if that creature is attacking, you may tuck it on top of its owner's library instead of returning it to hand. That converts a one-turn delay into a multi-turn one: the opponent redraws the threat next turn rather than replaying it the same turn, and against a land-light hand or a deck leaning on its draw step, the lost card becomes real attrition. The wrinkle is that the upgrade lives entirely inside the combat status check. The library mode only applies if the creature is attacking when the spell resolves, so the value is gated behind the opponent committing to the attack. Fire it on their main phase before attackers, or on your own turn, and you are paying three mana for a worse Unsummon. That gated reward is the whole point of the design: it pushes the spell out of the proactive tempo slot and into the role of a held combat answer, paying off the player who waits for the swing over the one who casts it on sight.