2 things
1) One time, after watching tv for a couple hours, I stood up, took one step, and fainted for what seemed like a microsecond. I had no control over my body. I came to about 1 foot from the tile floor and narrowly missed busting my face. I was absolutely terrified.
2) I used to get fevers all the time when I was a kid, and for some reason my parents wouldn't let me eat anything. The fever mixed with the lack of sleep and hunger resulted in the the most effed up fever dreams ever. Good memories, like having fun playing baseball, or my first day of school, would be sped up at least x4, and the voices would be low pitched, demonic-sounding, almost, but very fast and unintelligible. I would be practically screaming for the entire night, hallucinating terror-dreams until my mom made me food. It was scary as hell.