I think it's time to share one of Swim's personal delusions. This was experienced on a moderately high dose of DXM (10mg/kg) with cannabis and nitrous.
He found himself sitting in what seemed to be a classroom, but not for humans. The teacher and students looked...alien, but not in a sci-fi type of way. Just alien. The teacher was telling the students about the human race, and how their race had shared the planet Earth with humans since the dawn of time...and how, due to an accident of physics, they can see humans, but humans can't see them.
The teacher looked at Swim when she said this.
Is it possible? Modern physics tells us that there might be more than three physical dimensions, yet our little primate brains can only see three of them (plus time). Imagine creatures living in the sixth, seventh, and eighth dimensions, looking down on us, wondering why we behave so strangely. Or perhaps our brains can see these other dimensions, but learn to filter them out at an early age as "unimportant for survival."
Analogy: Flatland. Classic novel about a three-dimensional visitor to a two-dimensional world. The 3D visitor can perform what seem like miracles to the 2D people, like touching the insides of their bodies without breaking their skin. A higher-dimensional being might be able to heal tumors or put thoughts directly into one's brain. This might explain all the old stories about gods, angels, devils, elves, goblins, and spirits; plus the newer stories about UFOs and aliens. Perhaps better than the "skeptical" "oh, it's all just hallucinations" explanation.