Timesifter

Extra turns are usually the most tightly fenced effect in the game: pay a fortune, jump through a hoop, take a single additional turn and brace for the cost. This rejects the whole framework. There is no payment after the artifact resolves, no upper bound on how many extra turns it grants, and no guarantee the bonus goes to its controller: every upkeep, the deck with the fattest mana value off the top wins the next turn, and that arms race never stops. The design knot it ties is that an extra-turn engine becomes a random number generator. Whoever stacks the highest curve tends to chain turns, but a single cheap flip on the wrong upkeep hands the advantage back, so the card rewards building toward consistently large mana values rather than toward any one threat. The exile clause matters too: the cards burned to run the contest are gone, which slowly grinds both libraries thin and turns a long game into attrition. It is a symmetrical engine pretending to be a haymaker, an artifact that decides who gets to act before either player has cast a spell on their turn at all. Where Time Walk simply buys a guaranteed second turn for its caster, this hands the same prize to whoever wins a recurring lottery, a repeatable swing valve that punishes anyone who failed to build their deck around the flip it forces every single round.