Why do people with narcolepsy have those terrifying hallucinations?

The National Institute of Health says: Hallucinations can accompany sleep paralysis or can occur in isolation when people are falling asleep or waking up. Referred to as hypnagogic hallucinations when accompanying sleep onset and as hypnopompic hallucinations when occurring during awakening, these delusional experiences are unusually vivid and frequently frightening. Most often, the content is primarily visual, but any of the other senses can be involved. These hallucinations represent another intrusion of an element of REM sleep-dreaming-into the wakeful state.

I have “borderline” narcolepsy and let me tell you…those hallucinations are insane! Not usually frightening, but yes…just as I’m falling asleep or waking up they are most intense. And usually just really random!