Moonring Mirror

Almost no other artifact treats your own hand as a resource you reset on a clock. The trick is the two halves working against each other: every time you draw, the top card of your library slips face down under the artifact, so the longer you go, the more cards pile up in exile waiting to be reclaimed. Then, once per upkeep, you may trade your current hand for that growing stockpile, exiling what you held and pulling everything banked back into your grip all at once. It is a hand-swap engine disguised as card filtering, and the second clause is the payoff for the first: the draw trigger quietly loads a reservoir you cash in later. The face-down detail matters, because exiled cards are hidden information you reclaim in bulk, which turns the artifact into a way to stash answers and burst them back when the board demands them. This is artifact design probing what a permanent can do when the library and the hand are treated as separate banks to shuttle cards between, and the wording carefully tracks cards "you own," anticipating multiplayer and theft interactions long before that became common design vocabulary. The result is a five-mana machine that rewards patience and punishes nothing except a player who never reaches the upkeep button.