- See Good Witch of the North for details.
Her skin was drawn and wrinkled, and her hair white as snow. She lived a generally peaceful, humble, modest life, free of vanity and ambition; she served as the advisor and guide to the people of the Gillikin Country and settled their disputes. She kept a smallish (half-a-room sized) silver dragon called Agnes, and a two-tailed black cat with sharp green eyes, as pets.
She could not remember anything prior to the time when she defeated Mombi, the Wicked Witch of the North, and drove her from her cottage full of magic talismans and devices. Tattypoo moved into the cottage herself, and stayed for twenty years — until she recovered her previous identity as Queen Orin of the Ozure Isles. (The Giant Horse of Oz)
When Orin was a young princess, she became betrothed to Cheeriobed, then the prince of the Ozure Isles. Mombi caught a glimpse of Cheeriobed and, old as she was, fell in love with him; she took on the semblance of a young and beautiful woman, and tried to lure the prince into her clutches. This failed — Cheeriobed remained faithful to Orin. Enraged, Mombi placed the monster Quiberon into Lake Orizon to plague the Ozure Islanders, and kidnapped Orin.
Mombi tried to convert Orin into an old, ugly, evil witch like herself; but Orin's innate virtue prevented the transformation's full success. Instead, Orin became old and amnesiac, but a good witch rather than a wicked one. Catching Mombi in the act of turning a woodcutter into a tree stump, Orin/Tattypoo intervened, and found that her magic was stronger than Mombi's. She drove Mombi away and took her place, as a virtuous substitute, for twenty years. She would have been the Good Witch of the North that Dorothy Gale met early in her first visit to Oz.
It was only at the end of two decades that Tattypoo took Agnes's advice and looked into the cottage's magic window. There, she saw her previous existence as Orin, and she instantly jumped through the window to cancel the spell on her and return to her rightful life. (Agnes the dragon followed her, to return to her own normal life as Orin's maid in waiting. The two-tailed cat stayed behind.) The Giant Horse of Oz
After Orin's recovery, the role or position of Good Witch of the North lay vacant.
L. Frank Baum gave apparently-contradictory accounts of the fate of Mombi in his Oz books. In the second book, The Marvelous Land of Oz, he provided the famous and circumstantially-detailed account of Mombi's defeat by Glinda the Good. Yet in the fourth book, Dorothy and the Wizard in Oz, Princess Ozma states that Mombi was defeated by a Good Witch of the North. Ruth Plumly Thompson took this later hint as the inspiration of her story of Tattypoo.
Can the two versions be reconciled? Thompson writes that Mombi was "conquered" by Tattypoo, but not that Mombi was destroyed or her evil career terminated. (Chapter 7) This matches what Baum writes in Dorothy and the Wizard, when Ozma says that "a good Witch had conquered Mombi in the North...But Mombi was still my grandfather's jailor, and afterward my father's jailor." (Chapter 15)
After her defeat by Tattypoo, Mombi just moved, probably closer to the Wizard's Emerald City, and pursued a second phase of her career. She took the infant Ozma, transformed her into Tip, and was eventually defeated again by Glinda. According to Thompson's chronology, Tattypoo realized she was Orin two years after Glinda defeated Mombi. (Chapter 11)
Tattypoo was played by Miss Piggy, as were all the other witches in The Muppets' Wizard of Oz.