Napoleon (formerly Princess) is a minor character of Lucky Fred. He's Corky's cat which she mistakes his gender for being a female instead of a male, calling him "Princess" instead. He's very special and dear to Corky as she always talks about him and takes good care of him, despite that he's a male and he's irritated by every action of hers (like putting bubbles in his bathtub or dressing him up).
He appeared for the first and only time in Episode 21, Corky was going to use him as a key for getting voted by the students and therefore to get invited to an animal program which was going to choose a student for appearing on their show (with saying that she loves animals), but she didn't succeeded and Braianna got voted. but when Corky shows a footage with Braianna fighting with a cat (which was actually an alien named Fellinis) to the class, she puts Braianna's chance in danger. When Fred offers Braianna to throw a pet party to change the students' opinion again, on Braianna's pet party, Napoleon talked with Friday through his universal translator, telling him that he hates being treated like a female cat and he's very annoyed with Corky's "caring."
Braianna uses this opportunity to keep Napoleon until Corky calls Braianna, begging her for giving her cat back, Braianna makes two conditions, one to delete that footage and two, to treat Napoleon like a male cat (naming him as Napoleon and not Princess).