By the time Mishra was defeated, no mage was foolish enough to rely heavily on walls.

Fifth Edition

Battering Ram

Banding when attacking
If Battering Ram is blocked by any Wall, destroy that Wall at end of combat.

At the beginning of combat on your turn, Battering Ram gains banding until end of combat. (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding you control are being blocked by a creature, you divide that creature's combat damage, not its controller, among any of the creatures it's blocking.)
Whenever Battering Ram becomes blocked by a Wall, destroy that Wall at end of combat.

Introductory Two-Player Set

Rivals Quick Start Set

Renaissance

Rinascimento

Fourth Edition

Banding when attacking
At the end of combat, destroy all walls blocking Battering Ram.

Fourth Edition Foreign Black Border

Antiquities

Bands, but only when attacking. Any wall blocking Battering Ram is destroyed. Walls destroyed this way deal their damage before dying.