Metal Prison Rig

Metal Prison Rig enters the battlefield tapped
unless you control four or more basic lands.
{t}: Add {w}, {u}, {b}, or {r}.

"You will notice, earthbenders, that this rig is made entirely of metal. You are miles away from any rock
or earth. So, if you have any illusions about
employing that brutish savagery that passes for
bending among you people, forget them. It is
impossible. Good day" -Warden