Sentient book (Consequences)
In 2007, Nina Rogers found a sentient book in the library of Cardiff University. This book would take memories from individuals and convert them into stories. It formed a telepathic link with its victims, being able to steal their memories even when they were far away, and had a noticeable presence that Nina could feel in her mind. The book was obsessed with Torchwood Three, and tried to take as many stories about them as it could find.
In 2009, Ianto Jones found Nina, her friend Jess, and the book in the university library. The book had been stealing both of their memories, bringing them close to mental breakdown. Ianto took Nina and the Book back to the Hub, where they joined Jack Harkness in trying to destroy it. According to Nina, the book wouldn’t burn on a bonfire, couldn’t be fed to a man-eating plant or a man-eating fish, or damaged with bullets. The book was effectively indestructible.
To release Nina from the book's grasp, Jack decided to trap the book in a time-loop. He sent it through the Rift to 1899, where Emily Holroyd of the original Torchwood Three discovered it. Jack left a note for Nina inside the book, instructing her to secretly place it in Cardiff University Library, so that it could remain there until Nina Rogers discovered it around one hundred years later. (PROSE: Consequences)