Ali Baba

The whole card is one activated ability that taps a Wall, and that targeting line is a fossil of how early Magic built its rules. Before defender became a keyword, "Wall" was not just a flavor subtype but a load-bearing piece of the rules text: Walls could not attack as a property of being Walls. Tapping a creature keeps it from blocking, so this ability was an attacker's wrench, a cheap way to pry open the opposing defensive line that slow, wall-heavy decks of the era leaned on. The interesting seam is the design decision underneath: gating an effect on a creature type rather than on a keyword or a characteristic. When the 2004 rules and Oracle update rewrote how Walls worked, it decoupled the "cannot attack" rule from the subtype and handed every Wall the defender keyword instead. The Wall subtype survived the change and is still printed today, so Ali Baba's target has not vanished; what vanished is the meaning that made the ability worth a card slot. Hanging a rider on an evergreen keyword (flying, indestructible, defender itself) lets a card age into relevance as the keyword spreads; pinning the effect to a subtype whose entire strategic significance lived in a rule about to be rewritten did the opposite. The ability still resolves, but the world it was answering moved on, and the exact point where the rules shifted underneath it is still legible on the card.