Animate Wall

In Alpha, Walls could not attack because being a Wall was the rule: the creature type carried the no-attack restriction in its text, with no keyword to name it. This Aura exists to patch exactly that, handing a single Wall the permission to swing while white (the color of walls in the original color pie) does the editing. The narrowness is the entire design. Enchant Wall is one of the tightest target restrictions ever printed, narrower than enchant artifact creature, narrower than the tribal Auras that came later, and it ties the card's value to whether the battlefield holds a legal target at all. Modern design would not build this. The defender keyword (introduced years later to replace the Wall-type-equals-cant-attack convention) made the whole category of "remove the no-attack restriction" effects redundant, since a designer can now simply print a Wall that attacks. What remains is a curio: a one-mana white Aura whose job was to undo a rules artifact that no longer exists, preserved in the rules text because Wizards does not un-print cards. Reading it is reading the seam where Magic's original creature-type-as-rules-text design gave way to the keyword system that replaced it.