A constantly changing medley of real or imagined images.
There is a state between being asleep and being awake, a state in which dreams stop making sense and you feel how your body is tight in the rigor-mortal way that the body defends itself while unconscious. I have heard myself try to scream while in that state. The sound of trying to scream yourself awake from a nightmare is one of coldness. It is like a foghorn but without the authority. That state of the mind waking, the body sleeping, the deathly feel of heaviness and weight that almost holds you back in sleep — I call that phantasmagorical. Phantasmagoria.
I don’t like this definition’s use of the word “medley.” That makes it sound delicate, and while this in-between state could certainly be characterized as delicate depending on the content of the dreams I would think the word “mix” or the chemistry term “mixture” is more appropriate.
I think this word is more commonly used to denote psychedelic visions.