[kalkr]

You may be experiencing this? https://en.wikipedia.org/wiki/Hypnagogia

I have read a few anecdotal experiences of people allowing these kinds of hallucinations to continue and they have reported that they can become quite vivid and even interactive. Maybe try waving your arms around when this happens to see if it goes away? That should indicate if it's sleep-related or not.

[monknomo]

Sure, why not, though I fail to see much difference between that and dreaming