There's a good chance the freakiest things that happen to your body happen when you're ASLEEP. Which is good, because some of them are pretty weird.
1. Feeling like you're falling. You know this one. It's actually called a 'hypnagogic jerk.' It happens when you're about to fall asleep, and it wakes you back up. You feel like you're about to tip over, and throw out your arms and legs to catch yourself.
2. Sleep paralysis. Sleepwalking is when your body wakes up but your brain stays asleep. This is like the opposite, as if your body is paralyzed while you're dreaming. Sometimes you wake up from a deep sleep, and your muscles are still shut down. And at first it might feel like you can't BREATHE, because you can't move the muscles in your chest.
3. Sleep-talking. About 5% of us do it regularly, and it's usually within the first hour or two after going to bed, when you're already dreaming but the muscles in your throat and face are still working.
4. Sleep sex. Sometimes it's possible to wake up when you're already having sex. And YOU might be the one who started it. And it happens to about 8% of us.
5. Exploding head syndrome. Seriously. You wake up after hearing a really loud noise or maybe seeing a flash of light. You might actually have the sensation that your head is exploding. (ABC News)