A Nightmare thought & an episode idea for Black Mirror or the Twilight Zone... The Imaginary Boyfriend! And The Virtual Ex-Girlfriend...

So...

Here's the setup...

There is a guy, that has this girlfriend.. And while taking an hallucinogen, the guy decides or realizes or comes to the conclusion during his delusional/altered state that he isn't real...

His girlfriend takes advantage of the situation and plays a bit of a prank on the guy and tells him, "oh no dear, You're right, You are actually imaginary"

And she tells the guy he is her imaginary boyfriend that she created because she was lonely.

Eventually the imaginary boyfriend, the guy, breaks up with the girl, to prove to her that he is indeed real...

But years later after thinking that he has proved that he was real, The Mandela Effect starts to bother him and the guy realizes that he is not in the same universe anymore.

Skip to the end, the guy finds out that when he broke up with the girl that imagined him, that it somehow made him real and then put him into his own quantum universe where he was now real for real. And the girl that imagined him was now in a totally different universe where the guy never existed.

The guy ends up finding a way to travel to the universe where he was imagined from and once there, he does one and one thing alone. He drops by his ex-girlfriend's to let her know that it isn't him that's imaginary... It's her that's virtual!

And her world is actually a very sophisticated virtual simulated world, and when she imagined the guy, that virtual world literally created the guy as a real person, just as real as her, he was never imaginary, they were both virtual, and when he left her, it made the guy his own simulation to exist in.

Story ends with the ex-girlfriend standing in horror to the truth of the situation, which is that she never really existed either... As they are both technically imaginary beings as virtual people in a matrix of matrixes...

It would be like that old movie "Drop Dead Fred" but a nightmare version mixed with virtual reality :P Fred would be real and living in his own universe while he was trapped in the jack in the box...