Obelisk of Undoing

Buyback bounce, decades before buyback was a keyword. The activation is steep: six mana plus the tap to return a permanent you both own and control, an ownership clause that locks the effect to your own stuff and rules out the obvious abuse of stealing and rebuying an opponent's threat. What you get for that price is a loop engine on a one-mana artifact that survives most sweepers, since artifact-light board wipes leave it untouched. The design lineage runs through every "untap, reuse" enabler since: the Obelisk is the primitive form, asking you to build a deck where a single permanent is worth replaying every turn. In its era, that meant looping enters-the-battlefield artifacts and creatures, or rescuing a key piece from imminent removal at instant speed. The rate has aged into irrelevance for competitive play, but the bones of the idea hold up: a cheap artifact that converts excess mana into recursion, gated by an ownership clause to keep it honest. That restraint stands out from a set better remembered for its broken cards. Antiquities printed Mishra's Workshop and Strip Mine in the same packs; this is what a careful card from that era looks like.