Mary Alice Crosswire (or just Muffy Crosswire) is one of Arthur's friends and she thinks she's Smelly. She is the daughter of Ugly Ed Crosswire, that guy who sells Stuff.
She steals items on local websites, spends thousands of dollars to obtain porn, and often Kill her friends at school and even bullies the staff because she only thinks of herself. Everybody fears this spoiled brat, except for King Dedede and Mr. Ratburn: Dedede is even richer than Muffy so she worships him, and Mr. Ratburn sees all children as nothing more than things he can torture. She also admitted stealing all of the orange juice for the cure of cancer.