Trump, Builder of walls

+2: Tap target opponent's land. You add one mana of any color to your mana pool. Use this only to cast walls.
-3: Create a 0/5 wall token with defender and "This creature gets +1/+1 if you control another wall. If you control another wall, it can attack."
-9: Tap all opponent lands and summon X wall tokens where X is the number of lands tapped this way.