One of my vivid dreams (not really a nighmare) was a Tyrannosaurus Rex peering into my bedroom window with one of his big eyes. This dream came after watching Jurrasic Park for the first time.
I actually had a pretty unsettling dream last night. I was dreaming about the mountain that I normally go hiking on every day, and there were reports of people starting to disappear on it. Many people were warning me about the possibility of a serial killer being on the loose, and told me to stop hiking there because I might end up being the next person to disappear. Eventually, I went out searching on the mountain with a few other armed people, and we discovered an odd radio broadcast coming from some kind of storm drain or something. We followed the sound of it, and found our way into a derelict underground military installation. Then I woke up. I think this dream was a warning of some kind; I've been a little lazy and only carried a knife on my hikes. I made sure that I took my pistol with me in addition to my knife when I went out hiking today lol.