Rancid Rabbit is an authority figure who serves as the secondary antagonist in CatDog. He has such job titles as police officer, life guard, prison guard, firefighter, boss of various businesses, principal, president, mayor, Egyptian pharaoh, doctor, TV host, contest judge, store and Taco Depot manager, etc. In one episode, he appears as a principal at a school and, at the end, as a police officer. When Cat asks him about this, he never receives an answer.
Rancid hates CatDog and will go out of his way to punish them or force them to work for him, abusing his power to the fullest degree. Rancid takes advantage of CatDog as much as he can by deceiving them into buying his products or pushing them to do his bidding in a job. He does whatever it takes to take their money or benefit himself in any way. Rancid owns a mall called the Mall of Malls, and has a selfish and spoiled niece named Rancine. Rancid also has a Russian-accented female cousin named Rotten, who lives in Farburg.
- Billy West has confirmed that Rancid Rabbit's voice is based on that of the character Captain Binghamton (portrayed by Joe Flynn) from the 1960s sitcom McHale's Navy.
- He is similar to Congo Quint from Timon and Pumbaa, and the Devil from Cow and Chicken, because they're bad and have many occupations.