Originally posted by Travis E.
I'll be just falling asleep and my body will suddenly jerk for no apparent reason, which startles me awake.
Happens to me seldom. It's jerking from the onset of hypnagogic imagery to the waking state though I don't recall the hypnagogic imagery to be anything that would result in fear so, at least for me, it is merely a reaction to becoming to aware while drifting off and doing so too fast.