Comment by morjom

The waking up part is called hypnopompia and the falling asleep part is called hypnagogia. Hallucinations are known to occur during these phases between wakefulneas and sleep (e.g "I have hypnagogic/hypnopompic hallucinations") )

https://en.wikipedia.org/wiki/Hypnopompia

https://en.wikipedia.org/wiki/Hypnagogia