body that you've woken up. In an effort so as to not get injured in your sleep, your brain paralyzes your body so you don't act out your dreams and freak out.

Sleep paralysis is when your brain doesn't give the signal to cease the paralysis. So you're awake, but you can't move. Sometimes you can start to hallucinate as you're still half asleep, half not.

It goes away on its own. But can be quite alarming.