I remember reading stories about people who took a substance (can't remember which) and lived entire imaginary lives in a fantasy world in real-time: that is for years, they go to school, have kids, go to work, etc., until they wake up and it would have been only 15 minutes in actual life.
That's Dimethyltryptamine (DMT), the chemical produced by our Pineal Gland which is related to dreaming and is released in massive quantities upon birth and death (IIRC).
It's produced in several plants including Mimosa Hostilis and Acacia Confusa, and can be extracted into a tea called Ayahuasca, or into pure DMT crystals which can be smoked in a process similar to smoking meth.
People claim to have human experiences like you describe, but I've only ever gotten the type of DMT trip that completely unravels the human meaning of things.
Rick and Morty's Roy: A Life Well Lived is the only one reference I ever heard of. But its unsurprising - near-death experience produces some wild reactions and our minds love tripping around for some reason
