The sound of metal vibrating through the city streets became an announcement of impending disaster during the Martian invasion. Giant robots stalked the streets, destroying everything in its path. Moving slowly, with a Martian working the controls, the steel monster reached down and plucked terrified people off the sidewalks. Its huge pincers held any captive in a death-like grip until the Martian decided to apply the final squeeze. Powerful melting beams seared the buildings and left only rubble in their place. The robot, capable of crashing through brick walls, was made of an alloy unknown on Earth. Military weapons had no effect on the metal monsters.