i had this happen to me once about two years ago. i had a vivid dream i was somehow being possessed, and then when i woke up i couldn't move and i hallucinated some sort of monstrosity hovering over me. it was really hard not to panic since even breathing felt difficult and the visual part of it certainly didn't help. i really hope i never experience anything like this again :/
I've had this happen a few times. I've reached the point where once I feel it even slightly coming on I'll force myself to get up and move to a different room before falling back asleep