Spoon Oba-san, also known as Mrs. Pepperpot in English versions, comes from Alf Prøysen's Norwegian children's books, originally called "Teskjekjerringa" (Teaspoon Lady). She lives in a rural village with her husband, Mr. Pepperpot, a painter. Her life is defined by an involuntary and unpredictable shrinking to the size of a teaspoon. This sudden transformation happens without warning and reverses just as spontaneously after an uncertain time. Though initially confusing and challenging, she eventually accepts this as part of her existence.

When small, she gains the ability to speak with and understand animals, forging friendships with creatures like mice, frogs, bees, and a crow named Olina. Her magical teaspoon, worn as a necklace, remains normal-sized during her episodes, forcing her to carry it on her back. She actively hides her condition from other adults, especially her husband, fearing embarrassment, though he later discovers her secret. Children and animals are exempt from this secrecy; she befriends Lily, a mysterious seven-year-old girl living alone in the forest, who helps keep her secret.

Practical and resourceful, she often uses cleverness or negotiation to overcome problems while tiny. She shows kindness towards animals and children, assisting them during her adventures, though moments of frustration or sternness emerge, particularly when facing perceived misbehavior or stubbornness. While her adventures are mostly episodic, minor continuity exists, like retaining skills learned while small, such as swimming, for future use.

No significant character development unfolds across the series; her relationships, personality, and routines stay consistent, focusing on self-contained adventures. The origin of her shrinking condition remains unexplained, and the magical spoon's exact role stays ambiguous.