Hurkyl's Recall

Two mana, kept open through the opponent's turn, to undo a full attack's worth of artifact development: that is the asymmetry this card established, and the whole bounce-the-board lineage descends from it. Returning every artifact a player owns means tokens, equipment, and mana rocks all snap back at once, and the owner clause sidesteps the usual targeting trick of being handed your opponent's Juggernaut. The rate was a direct response to the early artifact arms race: Mishra's Workshop ramping into stacks of cheap brown threats needed an answer that could be cast on the same turn the attack arrived, where a sorcery-speed sweeper would have been a turn too slow. What it really codified is the principle that blue's answer to artifacts is a tempo blowout rather than permanent removal: the artifacts come back, the mana spent casting them does not, and the resulting turn cycle is often unrecoverable. The instant-speed board-reset designs that followed (Rebuild on a parallel axis, Echoing Truth on a narrower one, the perennial one-sided-asymmetry conversations around Cyclonic Rift) all sit in this card's shadow.