Nightmare
I don't generally have bad dreams. But last night I dreamt that I was traveling - adventuring? - with a band of people, not real-life people but dream-people, and as part of our journey we had to free climb this monstrous cliff. It was not a hard climb, really, and I don't recall being frightened by being a good 1000 feet up a rock wall with no rope. But then one of my traveling companions, a tall lanky guy, got one of his arms tangled up with mine. In extricating himself, he apologized, shifted a bit to the right, lost his footing, and fell. I woke up with his scream in my throat.
Scary.