S1·E53 Call of the Eternals

Ming sends a look-alike Defender ship to provoke the Beacon of the Eternals- a computer operated ship searching for a long lost benevolent society- which thereby releases its three Guardian Robots to retaliate against our heroes. The Guardian Robots are the most powerful form of robot in the known universe. When Flash destroys one of them, its strength transfers to the other two, increasing the danger to both the Defenders and the Earth. With one of the two remaining robots hot on their tail, L.J., Kshin and Zuffy fly to New York to retrieve Mandrake and Lothar, while Flash, Rick and Jedda lock the third robot in a force (stasis) field surrounding Monitor. In New York Mandrake defeats the second robot through a brilliant illusion. However, this was Ming's plan. The final Guardian doubles in size, draining Monitor of its power source and transforming itself into an unbeatable machine. Rick conceives a plan which the Defenders put into action- a homing torpedo is outfitted with a mock signal from the Eternals and launched into a black hole, thereby tricking the Beacon into sending the final robot to investigate the signal. The final robot is destroyed and our heroes and the Earth are safe from Ming's grasp- temporarily.