Post experiences which spooked you, which made you doubt reality, mathematical or physical laws, your sanity, memory or perception. The more improbable the better, but no second-hand legends please, share only what you personally experienced. If you had the event later explained rationally please use rot13 to avoid spoilers.
Yours is more spooky, but I had a similar experience.
In high school I had to get up early to be on time. In winter it meant waking up when there was still pitch black outside. Also, one teacher was exceptionally strict and would be angry at you for months if you were late or missed his class. So, when one day I woke up when there was fully bright outside I freaked out and jumped out of bed with a loud "F...F...F...". And then I woke up and it was pitch black outside. And then the alarm clock rang. I laid there for a while trying to figure out how the hell am I supposed to figure out whether I am awake or still dreaming. I didn't so I carried on ... maybe I'm still asleep, but at least I wasn't late.
This is a kind of "X files" thread.
Post experiences which spooked you, which made you doubt reality, mathematical or physical laws, your sanity, memory or perception. The more improbable the better, but no second-hand legends please, share only what you personally experienced. If you had the event later explained rationally please use rot13 to avoid spoilers.