Robot Attacks
A Positronix can issue a special kind of air-to-ground attack. At any time, a Positronix can convert some of the ships on their orbiting fleets to robots, at the rate of two robots for each ship. The robots will fall to the ground below and start killing humans, at the standard rate of four humans to one robot. Thus, each Positronix ship can effectively eliminate eight human population. (You cannot use all of the ships on your fleet in a robot attack; you must leave at least one ship behind to remain on the fleet key.)
If the Positronix thus kills all the population and leaves at least one robot standing, the Positronix will automatically capture the world--including all of its industry, metal, I-Ships, and P-Ships, not to mention any artifacts on the world.
This can therefore be one of the Positronix's deadliest attacks. Ships firing at a fleet performing a robot attack will fire and destroy the falling robots first (at one shot per robot), and then start to destroy ships remaining on the fleet.