His mother Amy Pond started killing when he became ill. For years she had been working as a morgue worker so she could feed off dead brains. These killings however attracted the attention of her old friend Sam Winchester, who stops her in a park. She manages to knock him unconscious, and quickly heads home. Sam follows her home, and demands to know why she's killing. She tells Sam she has a son and he needs the live food to save his life. Feeling for her, Sam lets her go. She quickly leaves with her son to a motel, where Dean tracks her down and stabs her in the heart. After her death and Dean's threatens that if he starts killing, he'll kill him too, but her son declares that the only person he'll kill is Dean, for what he had done.
- Jacob's promise to kill Dean in the revenge for the death of his mother, which he also witnessed, is a reference to Kill Bill Vol. 1, where the main character, Beatrix Kiddo, also killed a woman in front of her child and offered the child to get revenge when she's older.
- The act of trying to kill Dean over the death of a parent has presumably been taken by Cole Trenton, who appears in season 10.
- ↑ The Girl Next Door