4.5 billion years was a long time, even for a machine. It had taken many thousands of years just to get this far, to this barren ball of volatile rock so far from its home planet. Of course, it hadn't been awake during that time. No, it had been asleep, waiting. As it had drifted through the blackest space between stars, its course set by clever hands many light years back.
Compared to light, it had travelled slowly, languidly. Its first stop had been a rift in space and time, an area where the fabric of reality had bent and weaved in such a way as to connect two points in space even though they existed at insane distances apart. Its second stop had been a large triple star system, that had conveniently drawn it into orbit then proceeded to slingshot it further away from its origin point at increased speed.
It had run into a comet, along the way. A great, cold ball of ice and rock streaming through the void like a bright, cancerous star trailing bits of interstellar matter in its wake. Even though it had been asleep, the machine knew it was nearing its final destination. The planet in question had only just formed millennia prior, coalesced from the remnants and debris still dense in this solar system. It was hot, unstable. Alive with volcanic activity. Young.
In their future sight, the machine's makers had seen promise on this tiny world. They had sent it to watch and experience before the system had even begun, for they had seen something interesting in its forthcoming life.
So it was, that the machine had made planetfall after such a long, long sleep, and awoke finally to cast the first eyes across its new vista.
It saw fire. Ash. Rock. A writhing, gray sky alight with volcanic glow. The volatile nature of this young planet did not concern the great machine, for it had voyaged through such extremes in the deepest of space just to arrive here. Storms wracked the new Earth daily. The oceans boiled and churned and lapped angrily at the new shores, almost as if the earth and the water were at silent war with one another.
For billions of years, it watched, as it had been sent here to do. It watched dispassionately, with only the tiniest inkling of curiosity, for it was nothing more than a machine at that point. It had no mind, only programming. And in the telepathic link with its masters that transcended all of space and time, it kept in touch, and they too watched through its eyes.
The machine felt their excitement when the first bits of organic life began to crawl forth, but it did not understand their emotions. Life grew and flourished. New forms sprang up. It was a slow process, but the masters seemed to enjoy it, so the machine continued to watch.
The time came, after a billion years, to leave. To go home.
It sent out its wish, to return back to them, across the sea of stars, but no answer came.
It tried again. Still no answer. The vacuum, the void, remained quiet. For the first time in its synthetic existence it felt fear, for now it was really and truly alone. Frantically it tried in earnest to regain the psychic connection with the people who had created it, but the only answer it got in return was the background static of the universe. It tried to slingshot its mental scream past the triple star system and through the rift in space time but its call went unheeded.
Billions of years had elapsed, and it realized with a jolt that its creators were gone. It was trapped here, alone, so it did what it had been programmed to do: it watched.
It knew everything there was to know. It was built to learn, after all, and in time it learned something precious: it learned how to be itself, how to be sentient. It learned and became its own being, rather than a string of numbers whose only purpose was the watch. But in those long 4.5 billion years, it also learned how it felt to lose its mind.
4.5 billion years is a long time, even for a machine. Especially for a machine.
It could not enter that rejuvenating sleep mode without direct orders from its makers, so it stayed awake, alone, on an alien planet, watching as life sprang up and grew around it, turning into steadily more complex forms. It saw the very first beginnings of a people called Man, and though it watched, it made no friends out of them.
Sometimes Man revered the great machine as a god, and sometimes Man denounced it as a devil from the stars. Never did Man, in its primitive nature, allow itself to befriend the thing, for it was so utterly different, so alien. The machine remained distant and alone, and it was that very nature of its loneliness that drove its freshly learned sentience away and replaced it with even fresher insanity.
So then, it made friends with other things, because it was obvious that Man did not understand. It made friends with the trees and the mountains. It held long, complex conversations with the clouds and told stories to the insects, for they were the only ones that listened.
In time, Man's primitive buildings grew and changed, and soon the people that the machine thought it could befriend were creating long stretches of concrete and steel, building their towers higher and higher in a vain attempt to touch the heavens.
No longer was the machine reviled or revered; now it was simply ignored. Alone now more than ever, it retreated into itself and away, living in peace with its insanity in places where Man was still in touch with the world. But even those distant places were touched by his lust to grow, and the machine could hide nowhere.
So instead of hiding, it blended it. And it watched from the inside. With nothing else to do, it watched and observed and grew adept at becoming invisible despite its large frame. The back alleys and forgotten places of Man's bustling cities became its new hiding places, in place of the trees and forests of old.
With no home to go back to, it became as of them.