Phoebe Peeper, known as Asuka Satsuki in the original Japanese version, is a character in the 1981 anime series Superbook. She is the wife of Professor Frederick "Fred" Peeper and the mother of the series' young protagonist, Christopher "Chris" Peeper, and she is generally referred to in the series simply as Mrs. Peeper. The Peeper family lives next door to Chris's best friend Joy, making Phoebe a familiar adult neighbor and an everyday presence in the children's home lives.

In the story, Phoebe serves as a supporting family figure rather than a main character. She appears in the present-day household scenes of the series and does not take part in the time-travel adventures that are experienced by Chris, Joy, and the toy robot Gizmo. Her place in the narrative is tied to her family: her key relationships are with her husband, Professor Peeper, and her son, Chris, and she is also an acquaintance of Joy as the mother in the neighboring family.

The series offers little detail about her individual personality, personal motivations, or any development of her own. She functions as an ordinary mother living in a conventional family home, and no notable abilities, powers, or specialized skills are attributed to her. Her characterization reflects a maternal presence that supports the domestic setting around the younger heroes of the show.