In my life, I had two terrible nightmares.
My very first nightmare was very weird. I was on an old-school Korean bus traveling in Korea with my parents on it. Soon, we got to this small town/village that was near a creek with a stone bridge that went over it. I got off and my parents were gone. I was at the one of the bridge that may have been at most about 50 yards long. I saw a fairy at the other end so to get to it, I start crossing.
Next thing I know, she turns into a witch and blasts the bridge and I fall down into the creek with like 50 people! 
And then out of nowhere I see sharks in the creek and people are screaming trying to run away from them and same with me. I run along the banks and try to climb up… kinda like that recent Korean scifi monster flick “The Host” and … sweating, I woke up. 
I was very much shaken for several days due to that nightmare… anyone else with a nightmare to share?