I have experienced this very clearly once; about 10 years ago. I could 'see' something pushing me down & I was totally immobilised. My logical mind tried to convince me that this could not be real, since I do not believe in supernatural forces.
I'm glad that I have only experienced it once. I will not wish it on anyone to experience this. It was scary. You feel a total loss of control. My logical mind wondered after the episode if it may be a symptom of a potential heart attack or some other malady.
When I recounted this experience to some friends, some of them were surprised; but 1 of them was surprised that I had only experienced it once. He was a little shy to divulge more details.