I have had one specific dream since early childhood. I still wake up in a cold sweat after having it. Same dream each time. Did not understand it as a child but I understood the fear I was feeling when I woke up. Dark metal hallway with grates under my feet and flashing flickering lights. Suddenly there is a shudder and hallway starts to fill rapidly with water. I usually wake up right before it covers my head. Get cold chills just thinking about it.
Don't know why I have this dream but wish I didn't.