Repulse

Bounce-and-replace is the template that turned a tempo play into a no-card-disadvantage play, and this is the clean version of it. The math is what makes it durable: returning a creature to hand costs the caster a card, but the cantrip refunds it, so the spell trades only mana and a turn of an opponent's development for nothing of your own. That keeps it useful long after a pure tempo bounce has gone dead, because a removal spell you don't draw a card off of is a card-for-card exchange you might not want in a grindy game. Cast at instant speed, it does the work a counterspell can't: it answers a creature that's already resolved, sends one back so it can be replayed for its on-cast or arrival value, saves your own blocker by returning it to hand before a removal spell connects, or simply blanks an attacker mid-combat and leaves you a fresh card. The lineage runs deep on both sides of it: Boomerang did the bounce without the draw, Capsize did it repeatably, and later instants like Vapor Snag and Unsummon trimmed the cost while dropping the cantrip. Repulse sits at the value end of that family, the one that asks you to spend a little more mana so you never spend a card.