It's not clear who 'nip' is. It could be a name of a character, perhaps a small animal or a person who has some sort of interaction with the bear that is reading stories.
One possible 'kimber horror story' could be that Kimber was staying at an old, dilapidated hotel. As she was exploring the corridors, she noticed that the doors seemed to open and close on their own. In her room, she felt a cold draft even though the windows were closed. And at night, she heard faint whispers that seemed to be coming from inside the walls. It was as if the hotel was haunted by the ghosts of its past guests, and Kimber was trapped in the middle of this terrifying situation.
One horror story could be about a Kimber pistol misfiring during a self - defense situation. The owner thought they could rely on it but when they pulled the trigger at a potential assailant, it just made a clicking sound instead of firing. This put their life in immediate danger.
Definitely not. 'Tuck Everlasting' is a work of imagination. It was created by the author to tell an engaging tale rather than being based on real events.