Emperor\'s Prison

The Emperor’s Prison enters the battlefield tapped. The Emperor’s Prison does not untap during your untap phase. This land can only be untaped once per turn. Whenever a nontoken creature enters the battlefield under your control, if you control creatures with total power greater than 12, untap this land. {T}:{G}{G}{G}{flavor}“Others came here once. They built these walls. They played... alone. They bored me. Now they’re gone.” - Sea Emperor Leviathan