Shore Siege Gunner

You may choose not to untap Shore Siege Gunner during your untap step.
{u}{b}{r}, {t}, Sacrifice an artifact: Put a blast counter on Shore Siege Gunner
{u}{b}{r}, {ut}, Remove X blast counters from Shore Siege Gunner: For each counter removed, choose three target permanents an opponent controls. Destroy one of them at random.