The fear of being hunted is out of evolusionary remnants from many years ago. The fact that we did react to it is why we are alive today. This is your "survival instinct" at work and you see it in a dream.

I've had lucid dreams and sleep paralysis since about 15 years old, my top scary ones are:

1. Getting crushed across my abdomen by a lorry that tipped over and suffocating.
2. Throwing up clay, like normal vomitting but slow and painful, until my esophagus came out my mouth as well. Woke up while trying frantically to push it back in.
3. Accidentally drinking superglue and suffocating because my throat glued shut during swallowing.
4. Repeatedly getting false awakenings where I'd wake up, get ready for work, then go downstairs to find I was in my old house, and each attempt to wake up for real just made me wake up in a different dream, I started to think I was in a coma in reality or something. I eventually saw my mum in one of the dreams and asked her for help to get back to Earth. She replied, "Oh, that's where they have fire engines...and monkeys!" We laughed, then I fell into her arms and woke up for real. Not even late for work!

The evolutionary benefits would be working out solutions to problems, considering new possible problems to prepare a response to, and practice in dealing with potentially deadly or injurious situations in order to handle them better in the waking world. Considering that most people have nightmares when something is troubling them, it seems to follow that it might be a mechanism to help solve problems (if not directly, at least indirectly such as in an allegory) in the waking world.

I can't possibly guess which was my worst nightmare. I have severe PTSD, so mostly I have nightmares. My mother was a true terror in my life, and just dreaming that she is still alive is terrifying enough to count as a nightmare. Shortly after she died, I had a nightmare that I was rowing her in a boat while trying to dodge multiple waterspouts (tornadoes that occur in the water). Imagine just trying to out-row a bunch of those swirling all around you - now add that you are dragging with you an even worse horror, and charged with protecting her. Also, mostly the first few years after she died, I had nightmares that she hadn't actually died, but faked her own death to "catch" my father and me doing something she would have intentionally misconstrued as something she wouldn't approve of (and actually, this was not particularly implausible, considering how she really was).

Lots of nightmares about tornadoes, me drowning, people getting killed and it was my fault, one recently about the person I love most in the world (nothing romantic anymore, but someone I can't imagine living without) failing to come through on a promise to someone else, and I was trying to comfort him that he did his best, and him saying "No, you don't understand; I promised a piece of my head if I didn't come through" and then suddenly a portion of his head was shot off right in front of me, and I could see - uh, rather graphically, what happened. Maybe that one was the worst - or maybe it just seems that way because it was recent enough and is still pretty fresh...

Don't even wanna go there, too horrifying.

I been killed and since it was a dream... reloaded to try to save me but got killed again... I been in nightmares but they are no longer nightmare because they are dreams. I love dreaming. Specially the details of the dream. Like when I got visited by the future of mankind.... some kind of more fluid, watery shaped form of mankind. They examined me as if saying... "is this where we evolved from? they were not much would they?" I was laid on my bed looking at them. I checked the window for a spaceship but nothing. Dreams are good. Nightmares are exciting!!!!

I have a recurring, very realistic nightmare of living through a tornado.I guess nightmares are a way of getting exercise for the brain's "fight or flight" mechanism.

I don't take them too seriously so I've forgotten them.

I was sleeping on my back with my face covered by the bed sheet. I knew something had entered the room and was standing over me. I could sense it was menacing. I could feel it creeping closer and closer until its face was hovering right above mine, so close I could feel and hear its breath. I woke up nearly screaming, my heart was pounding.

I'm not sure there's an advantage to terror like that, however I've read that nightmares are one way your subconscious tries to work through things you're feeling, or problems you need to face.

When I’m stressed and overwhelmed I have the classic dreams where I’m in high school and either can’t remember my locker number or can’t remember my schedule to know what class is next.

I also have one where there’s a predator, usually a lion, after me. I finally make it to my house but can’t get the door open because I’m too scared and my hands are trembling.

I was in elementary school when the TV miniseries V came out. Early to mid 1980s? Ugh, had a recurring nightmare about it all through my school years.

All my life I was aware of a baby crying in the background. I thought it was a leftover from my childhood since my mom didn't believe in picking up her babies. But one day I was reading a book on past lives, where a psychologist was doing hypnotherapy with her patients, and suddenly people were remembering trauma from their past lives. She had them fix the past lives and their present problems vanished.

So I followed the book's suggestion, and simply decided to "see" the past life that originated the particular problem. I saw myself as a newborn Shawnee Indian baby that my mother, a teenager, had on the trail as a captive of a Creek raiding party that had already killed her family. The Creeks made her abandon the baby by the trail, and the crying was me.

So, I used some NLP techniques (used by the military for ptsd soldiers) and simply replaced the bad scenario with a good one..I imagined my mother returning to get me, nursing me, and raising me to have a happy life.

Afterward, the crying never returned.

I tried this for other puzzling behaviors, like an unreasoning terror of checking my finances, as I somehow thought it would get me killed.
The past life memory that appeared when I asked for the origin was when I was betrayed and killed when I withdrew money from my bank account before trying to escape with my Jewish family in the 1940s, in Belgium.
We were gunned down when we tried to reach the river to take the boat to escape, but when I googled the event, I found that our Belgian government had already sold us out to the Nazis, and all the people on the boat were gunned down anyway.

Anyway, I imagined no way or shooting and the fear went away.

I didn't care if it was "real" or not as long as it worked.

Dreamt there was some sort of living thing in my leg tearing it's way out. Very unpleasant.

IDK but that is a very interesting question. I never thought about it.