Hello and hope you are doing well.
What you are experiencing could be hallucinations and delusions and they can occur with certain medications, stress, sleep deprivation, in certain brain disorders and with schizophrenia or bipolar disorders. When sleep paralysis happens in sleep the person has difficulty moving his hands or feet. This is the symptom of a sleep disorder called Narcolepsy. You will need to consult your primary care physician for assessment.
Hope this helped and do keep us posted.
It sounds like relaxation, actually.