Robert Doyle is fat, but not obese. Despite that, he is fatter than some other kids. Robert has purple eyes and black hair. He wears red glasses, a light orange tank top, brown pants and blue shoes, similar to Bubble Bass' clothes from SpongeBob SquarePants. Robert's voice is similar to Bubble Bass, albeit much higher.
Robert Doyle is slightly lighter and softer than Francis. The reason for this is that while Francis, aside from bullying, is shown to break the law and steal, Robert does not steal or break the law, but he only bullies. He has small sympathy for the suffering of others. And, while Francis has a caring side sometimes, usually when he's alone, Robert has a remorseful and caring side deep down. Also, he had some mental toughness. He also likes eating large amounts of food, which explains his obesity.