If you mean one of those short dreams when you're just about falling asleep (you fall off a bike, you trip, whatever) - it's called a hypnic jerk: https://en.wi

If you mean one of those short dreams when you're just about falling asleep (you fall off a bike, you trip, whatever) - it's called a hypnic jerk: https://en.wikipedia.org/wiki/Hypnic_jerk https://en.wikipedia.org/wiki/Hypnic_jerk If you're talking about something else (full on sleep and waking up startled, then ignore me)