Spencer, originally Noriyasu Hatakeyama in the Japanese version, is a third-grade student whose life shifts dramatically upon acquiring a magical diary. This diary possesses supernatural power to manifest anything written or drawn into reality. His initial use conjures flying pigs; erasing most leaves one as his constant companion, Sunny Pig. This sets their core dynamic—adventures fueled by Spencer’s impulsive or imaginative diary entries.

His family includes unnamed parents, called Mom and Dad, and a younger sister, Tama-chan (Dizzy Lizzy in English). She often acts as an annoying sibling, though underlying care surfaces when she panics over his disappearance in a key event. Spencer navigates daily surreal chaos from the diary’s effects. Scenarios range from mundane disruptions like his family eating fried pencil balls for dinner, to bizarre encounters such as a world-domination-obsessed talking strawberry or a Samurai Lunch Lady.

Spencer’s development focuses on managing his power’s consequences. Early episodes reveal his lack of control causing unintended chaos; later narratives show gradual, inconsistent growth in responsibility. He repeatedly thwarts schemes from Kimiyo Hiraga (Tiffany Van Hootenberg), who harbors intense, unreciprocated romantic feelings. The series finale escalates his arc when an incident erases his family’s memory of him, with resolution left undefined.

He appears consistently across all 61 television episodes and features in a 1988 animated film adaptation. These constitute his documented appearances.