Coby Brooks is the youngest brother of Willie Brooks and is diagnosed with Chibi Toddler Syndrome: a condition that causes not only mutation, but many development delays as well, therefore functioning like an infant no matter how many years go by.. He is known to be fussy, needy, whiney, hissy, nonspeaking, bloaty, picky, loud, and obnoxious. Coby would throw a huge tantrum should he not get his way, and is always picky about almost anything. He also uses the bathroom on himself, constantly, which means he has to wear diapers and have someone change him. Willie hated his brother because of the attention Coby receives, so he bullies him a lot, breaking his toys and shouting at him, even getting physical on Coby. When their mom passed away, Coby was taken to an orphanage and was being treated poorly by the staff and children. Fortunately, Willie began to heal his own problems and took him in once more, claiming ownership of Coby. Willie tends Coby's needs but does discipline him when he misbehaves and making him change his own diapers.