*When humanity first explored the Andromeda Galaxy they met a number of alien species, but non more fascinating as the Mechan.
Here was a species that was totally machine, for they are a race of robots built by the long extinct Goboran’s.
The Goboran’s settled the gas cloud we call Deep Shadow Nebula well within Andromeda space.
As more planets were explored and settled, they spread themselves across space, leaving behind their homeworld of Goboran.
According to Mechan history the robots were built to do nothing other than explore and assimilate the planets and moons that they found.
This was done by the robot Mothership sending a “pod” down to the surface, this construct established a foothold and sent out tendrils across and under the surface.
What they did was process the minerals and develop more “pods”, asimilating the whole planet/moon.
Once this was done, the “pods” were then brought together to form cities to await the Goboran settlers.
And as the Mechan program was never changed the robots have continued asimilating thousands of worlds, when the construct begins its city building, the Mothership moves on to new worlds.
One good thing we did learn was that they pose no threat to other beings settled worlds, as they only asimilate planets/worlds devoid of sentient life.
This could go along way to explaining why in our own explorations in the Andromeda Galaxy we found many planets with large but vacant cities.
And another plus is the fact that we can settle these worlds ourselves, the Mechans are non-aggresive only programed to colonize and build.
As an aside, some of the constructs look very similar to the Great Pyramids of Earth*