Wall of Vapor

Rather than printing a Wall with a large toughness (the standard solution to blocker design, then and now), Legends tried a different tack: hand the blocker a localized damage-prevention shield so its toughness number stops mattering against whatever it chumps. A 0/1 body becomes, in theory, an immovable obstacle to any creature it blocks. The prevention is scoped to the creatures the Wall is blocking, and it is total within that window: it stops not just combat damage but any damage a blocked creature would deal to the Wall, including damage from an activated or triggered ability. The text says "creatures it's blocking" in the plural, so if the Wall is somehow granted the ability to block multiple attackers, the shield covers all of them at once. What it does nothing about is everything that routes around the block: trample, burn, pingers, a creature attacking past it. That narrowness is the design's whole defense of the rate, and the rate still loses the argument: contemporaneous walls were already offering more toughness per mana with no conditional text, and the prevention clause does not scale into any interaction that matters. The card reads now mainly as a snapshot of a moment when damage prevention was still being priced as a premium effect worth real mana, before the toughness curve on defenders caught up and made the entire conceit redundant.