I intend for this to be my entry into the SCP-5000 contest if it all goes through.
The Administrator is real, kind of, not really. The Administrator exists as a sort of intangible force embedded deep in the consciousness of everyone who holds a position of power in the Foundation, sort of like a hive mind except if a hive mind takes over your whole mind, this just takes over 0.01% of it to lightly push you in certain directions and collect together to form its own singular consciousness in the nebula. The story is told from the perspective of a Chaos Insurgent embedded as a Foundation researcher, trying to uncover who The Administrator is so they can assassinate him.
The information on what The Administrator is and how this all works is dulled out very slowly as the Chaos Insurgent delves deeper into SCiPNET. The Administrator catches on to this and starts showing exerting its influence in an attempt to stop him, which itself provides more details and hints towards what The Administrator is. At the end, the Chaos Insurgent is caught and assassinated, the Foundation decides to archive all of these memories and collective knowledge as SCP-5000, as they previously only had the vaguest idea of what The Administrator was.
EDIT: I thought of a slightly better way to explain what I mean the administrator is in this article, it's called the Gestalt Administrator so the best way to show what I mean is with the gestalt principle; In this picture, is there a star, or is it just a bunch of pac-men? In literal terms it is just the pac-men, but if you show it to anybody they could clearly see the star. Imagine the pac-men are the Foundation and the star is The Administrator, it exists because of a confluence between an uncountable number of personnel, and has influence over them as the star is now it's own entity partially residing in all of them.










