Humanity's space exploration ultimately took the form of billions of identical probes, capable of building anything (including astronauts themselves) upon arrival at their destinations. One lands in Equestria. Things go downhill from there.
A creature of old has been present in Equestria since the beginning of the rule of the alicorns, watching, waiting. He saw their fall and the sisters' rise to power. Now, for the first time in eons, he steps from watching and takes action.
[Prototype 2]/MLP crossover. One of Alex Mercer's Evolved gets sent to Equestria, stricken with an obsession with security, can this untrusting being ever find peace if he does not allow himself to?
Steel doesn’t worry about a colt’s well-being. Railroad cars don’t have much concern for the bodies of ponies. But, despite the dangers, I wanted to be a railway pony. I wanted to be like Highball.