Hypnagogic hallucination is episodes of seeing and hearing things as one is falling asleep. These dreams can be frightening and can often cause a sudden jerk and arousal just before sleep onset. For example, you may see yourself falling and awaken with a sudden jerk, just before impact.
I started to fall asleep one time and as things started to fade I heard someone call my name. This freaked me out, because it sounded like my father (who at the time was asleep). Despite having lucid dreams I wasn't aware of these kind of things, so I was really freaked out. Has anyone else ever been called as they fall asleep?