I've always been a fan of the random unexplainable creepy with things like this.


They wake up while camping and there's a coffin next to them. Child size of course. They find dolls of themselves in the woods or in their bag.

While traveling whoever rolls highest perception hears something. When the group investigates, they find a hurt animal or tied up villager. Just before dealing with it, stop the encounter. "Okay, everyone who isn't Jacob the Knight, you didn't realize he had walked off into the woods, but clearly his footsteps go that way." The entire thing was imagined by the player who rolled high. The others come across him acting like he's freeing the person or helping the animal. Until they shake him awake as if he's sleep walking.