Yes, I once had a bad dream where I was trapped in an underground cave. At first I did not know where I was. It was very dark and small, and I could hear water dripping. I was very scared, and immediately started trying to look for a way out. I could not find any sources of light, so I started pressing up against the walls, hoping that there would be a hole somewhere. I remember feeling as if the cave was getting smaller and smaller, until it was so cramped that I could not move. Instead of panicking further, I lay still, and slowly the cave started expanding again, until I could see a pinprick of light above me. I pushed and pushed until I could claw my way out of the top, but as I reached it, the whole thing collapsed under me and I felt the sensation of falling. I woke up with a fright.
That was 801 characters. I hope it helps!