Walls

Minions with Wall cannot move, and is immediately removed from the battlefield if dispelled. They are generated by certain spells and monster effects, and thus are tokens. There are four different types of Walls.
 * Walls are used to block your enemies' movement and can be Transformed or buffed.
 * Walls can be given buffs available to any other minions, such as Primus Fist's and Razorback's effect or Frostfire. In addition, Winter's Wake will buff only friendly Walls.
 * If a Wall is returned to its owner's action bar (e.g. by Hailstone Prison), it becomes a minion that can be re-summoned.
 * Each Wall is considered as a summoned minion in terms of triggers (e.g. Bonechill Barrier triggers enemy's Venom Toth 3 times).

Strategy

 * Enemies often avoid Walls, so you can use them as a zoning tool.