It was probably because I was having vivid dreams and woke up abruptly. When I was younger, I did clearly see a large floating picture frame disappear into the wall just after waking up. I think that's a form of sleep related hallucination most people can experience, I just don't remember what the phenomenon is called.

Earlier this year I did start seeing letters and characters written all over the surface of things, including my own skin. It wasn't vivid, but after I stopped seeing it, I haven't seen it since. It's only because that happened that I made this topic.

I much more prone to magical and delusional thinking than hallucination, but I wonder.