Invasion of Lorwyn // Winnowing Forces (March of the Machine)

Battle Ñ Siege // Creature Ñ Elf Warrior - Invasion of Lorwyn: (As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When this Siege enters, destroy target non-Elf creature an opponent controls with power X or less, where X is the number of lands you control. // Winnowing Forces: Winnowing Forces's power and toughness are each equal to the number of lands you control.