Time Stretch

Extra-turn spells run a spectrum from Time Walk's broken efficiency down through Temporal Manipulation and Capture of Jingzhou, and this one sits at the far, deliberately expensive end: the version priced so the effect can exist without ever threatening fair midrange. Ten mana for two extra turns is a number meant to cap a ceiling rather than to be cast on curve. The number that matters is two, not one. A single extra turn is a tempo swing; two is a window long enough to assemble a kill that does not yet exist on the board, so the card belongs to combo and ramp shells rather than tempo decks. The "target player" clause is the genuine wrinkle: the turns can be handed to an opponent, and while that reads as a downside, it makes the card a political tool and an enabler for any strategy that profits from a forced draw or a poisoned gift. The cost does most of the constraining: at ten mana the spell does not bend the game so much as conclude it, and if you can pay for it you are usually already winning, with the two turns serving as the formality that converts an advantage into a finish. It is a finisher dressed as a tempo card, priced so the disguise never fools anyone playing for value.