“Sleepy” hallucinations are also called hypnagogic imagery, referring to the transition state between awake and asleep. There are other types of “normal” hallucinations, too. Many mentally healthy people will hallucinate at some point in their lives. The whole subject is fascinating.
If you’re ever lying in bed and you close your eyes and you see purple or green Rorschach-like shapes moving and changing like a lava lamp, that’s a hallucination most people have regularly.
Mine look like this usually
I got these last night I saw a small cat running around a couple times and a man standing by my bed. Creepy
Source: Ultra Facts