All human stories and ideas seem to have a life of their own because in a way, they do.
Long ago, life evolved on a death world, Earth, and the aliens of the galaxy feared us. Their greatest weapons didn't stop our planet from creating sophont life; even their last ditch attempt to wipe out our biosphere only killed off the dinosaurs, and monkeys took the lead a mere few hundred million years later. It didn't last.
So they tried a new tactic. They built a gigastructure around our solar system, traveling with it, a truly titanic version of their psychic entertainment brains, in the hope that it would keep us occupied with whatever fiction we created, too interested in chronicling the adventures of our favorite characters to move beyond our planet.
The first indicator something was wrong was when the storage began filling up faster than expected. Then again, humans had just invented mass communications in the form of printed books; it made sense that they'd see an initial spike in simulations. Frankly it was taking an embarrasingly long time for them to reach that point, and the Council was beginning to fear their idea might've been too successful.
That fear was replaced quickly once humans started running simulations of spaceflight and FTL on the brain. They didn't even know they were doing it, a few of them just had otherwise interesting ideas that the brain then picked up, and despite its aim of distracting humanity it could only do so much to obfuscate how reality worked. At some point, if made it too unlikely, the humans lost interest.
And the Council had sealed it from external control, fearful of a couple of the lesser (than Earth, anyways) Deathworlders working to free their brethren.
Even this might not have been such an issue, until one day the humans managed to figure out interconnected networks, almost subconsciously, from the brain's psychic feedback.
The Internet was born. All was somewhat worrying, but still manageable, for about 30 Earth years.
Then suddenly, the number of simulations went exponential inside a single decade. Permutation upon permutation, run through billions of human minds each with their own way to process and see the world, started rapidly filling the previously unthinkably expansive storage of the brain.
And the population of the galaxy could only watch on in horror as fan fiction and battles of theory turned the human species into a collective tactical, logical, and genre savvy race of masterminds while the brain's systems sped towards their maximum at a pace never seen before....