Cracked Techfield

As Cracked Techfield enters the battlefield
you may sacrifice an artifact. If you do not,
Cracked Techfields enters the battlefield tapped.
{t}: Add {b} or {r}.
Molten metal flows through the ruins of what
was once a thriving production site. But the machines
saw its use and devoured it. Leaving nothing but
whats left of the metal that used to supply it.