Weather can also create camping horror stories. Sudden storms can be terrifying. Lightning strikes close by, strong winds that threaten to blow away your tent, and heavy rain that floods your campsite. Also, hearing strange noises at night. It could be the wind in the trees, but your mind might think it's something more sinister like a ghost or a monster. This psychological aspect is very common in camping horror stories.
Running into other people can be a horror story too. There are some cases where campers encounter people who seem a bit off or who might be up to no good. For instance, I heard a story where a group of campers were visited by some strangers in the middle of the night asking for things in a rather menacing way. It makes you feel very vulnerable when you're out in the wild and away from civilization.