Hypnagogic hallucinations are sensory experiences that occur just before falling asleep. Individuals having a hypnagogic hallucination have visual, auditory, or tactile sensations as they are falling asleep. The sensations may be strange or bizarre. It is also common to experience sleep paralysis during a hypnagogic hallucination. Sleep paralysis is the inability to move though you are conscious - it is essentially the mind being awake while the body is still asleep. Hypnagogic hallucinations can also be a symptom of narcolepsy. The opposing concept to this is a hynopompic hallucination which occurs while waking instead of falling asleep.