The stranger
Me and a friend were on our XBLA world, and for his sake I will call him 'Netherrack' and me 'Glowstone'. We were making a quarry and had made a storage/main room, a bedroom, and a small hollowed-out room. Making stairs down, I found a cave. I should have known it was trouble.
Later…
Me and Netherrack entered the cave, and even though we were on creative, I was scared into saying "Netherrack? I think we should leave now." "Glowstone, it's fine." After supposedly hitting a piece we had already 'found'.
At this point, I quit from Minecraft claustrophobia. Like regular claustrophobia, but in Minecraft and only in mines. Inconvenient. Everything after this is fiction.
"Netherrack? These torches weren't made by us. Netherrack? Netherrack!" He was gone. Suddenly the torches went out and I was in darkness. The next thing I knew I was in a different cave, with Netherrack. "G-g-glowstone? He's here. He's always here!" "Who?" "The stranger."
I don't remember anything else.