Wall of Wonder

The clever bit here is the activation: a Wall that pays mana to become a 5/1 attacker for a turn, then snaps back to a 1/5 blocker once the stat change wears off. Legends was full of cards trying to break the wall-as-defender mold (animation auras, the occasional Animate Wall), and this one folded the trick onto the creature itself, eliminating the two-card setup. The +4/-4 swing is the structural pivot: it inverts the stat line cleanly, which is both elegant and what keeps the card from spiraling out of control. The animation is strictly temporary; the toughness penalty expires once the turn ends, returning the body to 1/5, so you cannot stack the effect on the same turn without killing it (a second activation drops toughness into negative and the creature dies on the spot). What you get is a mana sink with a built-in clock: a defensive body early, a finisher when the game stalls and the blue deck has spare lands to dump. The shape prefigures the "manland" idiom that Mishra's Factory had already established for colorless and that later land cycles refined into a format pillar. This is the creature-side version of the same idea: a permanent that idles cheap and converts mana into pressure on demand. The rate is slow, but the design instinct (a body that does nothing until you have the mana to make it threaten) is one Wizards has returned to repeatedly.