Patty (The Super Mario Bros. Super Show!)
From the Super Mario Wiki
One day, Patty randomly appears at the apartment of Mario and Luigi, claiming to be an orphan without a home. After hearing Patty's story, Mario and Luigi, feeling sorry for her, especially after hearing it is her birthday, decide to throw her a party, with Patty demanding a large amount of expensive things for it.
Eventually, after getting everything she wants from Mario and Luigi, Patty becomes upset. Eventually, Patty's actual parents, who reveal Patty to be a chronic liar and troublemaker, appear at Mario and Luigi's apartment.
After learning what trouble Patty caused, her parents ground her "'til the end of the century illegally" and make her apologize to Mario and Luigi. Despite all of these events, Mario and Luigi still decide to throw a party for Patty and her parents, since they already have everything set up.