I had some surreal dreams when I was on metronidazole. In one, I was in a tall stone tower a bit like a lighthouse. Inside it had a ramp like a spiral stair case without the steps, and my feet were able to glide over it like they were on roller skates, but without the skates. I went racing down the ramp, shot out of the door at the bottom, and raced down a big hill. In another, I was flying. Great fun.
Some mornings I get strange visual images when I'm wide awake after I first wake up. Sometimes, jet black images of the blood vessels in the retina flash each time I blink, other times I see a constellation of red and green pin dots as if the cones in the macula are firing. If I wake in the night, I sometimes see what looks a bit like a spider the size of a saucer on the bedroom wall. The opticians have no idea what they are. For the last 20 years I've also been getting ocular migraines, which are something else entirely different again.