Marilyn (The Super Mario Bros. Super Show!)
From the Super Mario Wiki
Marilyn is a young, party-going woman who dresses in leather and listens to loud rock music with her gang of four unnamed friends. She is also a niece of Mario and Luigi's. It is suggested that she is related to them through her mother's side of the family, but this relationship is never fully explained. She was played by Moon Unit Zappa, best known as the daughter of rocker Frank Zappa.
During the events of "Wild Thing", Marilyn shows up at Mario Brothers Plumbing one weekend, meeting up with her two uncles for the first time in quite a while. Despite being uninvited, Marilyn explains that her mom told her that they wouldn't mind if she and her friends stop by for the weekend. Before Mario and Luigi can object, Marilyn's friends join her in Mario Brothers Plumbing and proceed to dance with her to her loud music.
Marilyn and her friends are oblivious to the fact that Mario and Luigi are perturbed over their arrival and keep on dancing. She eventually asks Mario and Luigi if they want to join in, but they decline. As her party is greatly annoying them, Mario and Luigi eventually decide that Marilyn has to leave. However, neither of them want to tell their niece to leave, and opt to draw straws; the loser has to speak to Marilyn. Luigi, however, rigs the straws to make Mario lose.
Before Mario can convey his message, Marilyn announces that she and her friends are moving the party to the beach. Luigi notes that Brooklyn has no beaches, only for Marilyn to state that they would be staying with her Uncle Troy in California. With that said, Marilyn and her friends leave Mario Brothers Plumbing, leaving Mario and Luigi in peace for the time being.