Nanette Musette is the hidden main villainess from "The Nutcracker Scoob," the Christmas-themed finale of The New Scooby-Doo Mysteries (airdate December 1, 1984).
Nanette Musette is a maid working for miserly Winslow Nickleby, who was looking to purchase the childrens home at Christmas Eve. She overheard Nickleby's lawyer mention a priceless emerald hidden at the home, and it was at that moment that she decided to steal it for herself, doing so by dressing as the Ghost of Christmas Never and scaring those at the home.
Nanette's first appearance came during the gang's rehearsal of A Christmas Carol, scaring Shaggy and Scooby, among others. Believing that the emerald was in a star in the attic, the evil Nanette resurfaced in the attic and took the star, which was reclaimed by the gang, who discovered that no emerald was inside. Nanette performed her duties at the night of the play, taking coats at the front door, only to resurface in her villainous disguise and take the antique nutcracker, after learning that the emerald is inside. The gang chased the villainess, who was attempting to get away on a sleigh, but she was stopped and later unmasked.
After her reveal, Nanette stated that with the emerald, it would have been Christmas every day, and she was later arrested.