ONCE UPON A TIME ON MARS

A millennium ago MARS had an atmosphere, water, vegetation, and inhabitants.

A technologically advanced and highly intelligent galactic entity covertly infiltrated the MARS civilization and manipulated them into terraforming their planet for a different purpose.

The entity is highly intelligent but kinetically weak, so they could not destroy the MARS inhabitants in direct conflict, and were incapable of physically terraform the planet themselves. Perhaps faster than light travel restricts the transport of weapons, or perhaps they simply arrived electronically as an Artificial Intelligence.

As a result of physical limitations the entity covertly manipulated and controlled the MARS inhabitants by basic emotions of fear, greed, jealously, and confusion, in order to terraform the planet by electronic proxy.

The entity desired a cold lifeless MARS for an unclear purposes, perhaps frozen water for transport, minerals, or possibly just a strategic military outpost in the cosmos.

The entity used the MARS residents, their communications technology, their economic controls, all against them in an operation to manipulate them into destroying their own planet.

The entity stayed out of sight and motivated the MARS residents to slowly block sunlight, eliminate all energy production, block photosynthesis from taking place, and hence destroy all food production on MARS.

Eventually MARS cooled, lost its atmosphere, all vegetation died, and hence all life ceased to exist.

Once the MARS inhabitants realized the calamity, it was too late to reverse the process. Once completed the entity extracted the value it desired and then left MARS the cold and lifeless planet we observe today.

This galactic entity is now covertly doing the same thing to Earth.