Ensnare

Tapping every creature on the board is the kind of effect Magic almost never sells cheaply: a mass-Fog that freezes an alpha strike or strips every blocker before one. The printed four mana is the price you are not supposed to pay. This belongs to a family of cards that let you trade Islands for free spells (Daze and Foil pitch toward countermagic, Submerge toward creature removal), and this is the combat member: bounce two Islands and the effect costs nothing but tempo. That tempo is the real bill, and it is steeper than it looks. Two lands off the battlefield is a genuine setback you can only stomach while sitting on enough mana to absorb the loss, which is why it wants a control shell long enough to rebuild over the following turns. The instant speed is where the symmetry stops being symmetrical. The text taps all creatures, including yours, but you choose the resolution window: fire it once the opponent's turn has wound down and your team untaps on your turn while theirs stays locked, converting a "fair" board-freeze into a one-sided swing back the other way. What lingers about the design is the question it puts on the stack: how much is a turn of frozen combat worth when the cost is paid in lands instead of mana, and who gets to untap first? That trade has been a recurring experiment in pricing power, and few cards state the terms this baldly.