Penny Fitzgerald is kind and warm-hearted. She is friends with all the girls (except Tina ) and is shown to be friends with some boys such as Gumball (whom she likes), Darwin, and Leslie. She also got visibly upset when Gumball turned her down in The Pressure and The Party . She stuck up for Gumball in The Gi while he was being teased about his martial arts uniform, suggesting that she has a sense of justice and good morals. She is not a very good painter.
Penny is a peanut with antlers that resemble cacti coming out of her head. The reason she has antlers is because she is a doe-nut - a portmanteau of doe, a deer, and nut, as in peanut. Her eyes and mouth are just hollowed out holes that resemble coconut holes. She also has light brown arms and legs coming out of her. Her peanut shell is a lot like a turtle shell; it is both a shell that she lives in and it's part of her body. She is often seen wearing her pom-poms outside of cheerleader practice. Now seen in Season 3, she is like a orange shape of herself but can change due to her emotions seen in the episode The Crack when they first show her true self.