Defenders of the Earth S01E53 - Call of the Eternals

The Beacon of the Eternals is a computer-managed ship that belongs to an ancient civilization. Ming provokes the ire of the Beacon by sending a ship to attack it that is disguised as the Defenders' ship. The Beacon then proceeds to return fire by sending three Guardian Robots to neutralize the Defenders. Not knowing why they are being attacked, the heroes must fight back, but the battle against the robots proves to be a near endless one!