Martial arts training camp. Average sleep time was around 4 hours per day, also, guard shifts round the day, so sometimes it ended up being 2. So towards the end of the week I was quite... sleepy. And this seems to have an interesting effect on visual pattern recognition.
One day, me and another guy were standing guard, around 4 in the morning, the sun was just about to come up. Making circles around the countryside weekend house we were staying in, I noticed that some people appeared with a truck and started to pick grapes from the nearby field. I promptly went and reported it to the other guy, so I was pretty sure of this observation, until I went back, and...
the truck and the people somehow turned into grapes and new people appeared to pick them.
Later that week I actually made up a rule saying "the guy standing in front of the house is, regardless of how much he seems to move around, a tree". Since I actually went there once and checked previously. Science over unreliable visual cortices...
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.