The Greaser Dogs are a street gang consisting of three dogs named Cliff, Shriek and Lube. They serve as the main antagonists in the Nickelodeon cartoon series, CatDog next to Rancid Rabbit. They act no differently than school playground bullies, picking on anyone either weaker or different than them. They pick on and beat up CatDog. Their usual nickname for them is "Catbutt", because Dog has Cat for a butt. Dog sometimes gets along with them because he's a canine, as well. They initiated him in the gang, after he had proven his worth as a "real" dog. Three members are tough, loyal to the pack, and are proud to be dogs. Eddie the Squirrel wants to be a Greaser dog, but isn't accepted by the group (probably due to being a squirrel).
In "The Great Parent Mystery", they follow CatDog in their quest to find their parents, hoping to beat up them up along with their parents. But when CatDog, along with their Sasquatch mother and Frog father, escape on Old Uppenchuck, the Greasers, along with the Catfields and the McDogs, get eaten alive by Bessie the Lake Monster. It is unknown if they ever escaped the monster's stomach.
- Clifford "Cliff" Maurice Feltbottom (voiced by Tom Kenny): The leader of the Greasers who is a deformed bulldog. He wears a black leather jacket with a picture of a dead cat on the back of it. He is very short tempered and speaks with some sort of Brooklyn accent similiar to Winslow. Eddie was accidentally glued to his jacket which them turned into "Squirrel Dog". Once this happened, Shriek and Lube kicked him out of the Greasers because he was a two-faced freak. However, once he was free from Eddie, he returned to his old bullying ways and re-joined the Greasers. In another episode, he volemnly vowed to never bully anyone again but it didn't last long. In later episodes, soft sides of Cliff have been revealed, such as love for ballet and cashmere. The episodes "Adventures in Greaser Sitting" and "Back to School" proved that he's not an only child, as he had a niece and a nephew.
- Shriek Dubois (voiced by Maria Bamford): The only girl in the Greasers. She is a tiny white poodle, with a high-pitched, squeaky voice with a slight raspy quality to it. Though she's as tough and loyal as the other two, she's very emotional romantically and has a crush on Dog (though he never appears to notice) and frequently hides it from the other Greasers. Shriek will not hit Dog, she'll only hit Cat. In the episode "Rich Shriek Poor Shriek", she came from a rich family, but she didn't like the posh life, so she left home and became a greaser. She pointed out to Cliff and Lube that she's actually a girl, in which both Greasers finally realized it and screamed.
- Ignatious "Lube" (voiced by Carlos Alazraqui): A hound dog, and the slowest and sweetest one of the group. He'll forget what he's saying and slur his speech. Despite this, however, he can speak perfect Spanish. He's the most loyal of the three Greasers. Despite his dull wit, like his parents, Lube has lots of musical talent and can sing very well. It is important to note a character design modification that occurred after the first episode, in the premiere episode "Dog Gone", Lube appeared with black dot eyes and long brown hair that extended down to his nose. In subsequent episodes, his appearance was changed and remained that way until the end of the series. In one episode he rolls up his right trouser and takes off a wooden leg. He also works part-time as a mechanic. His parents, a cat mother and a dog father, appeared in the series finale and said that Lube got separated from them a long time ago. Also in the series finale, Lube is shown to have had a sister, who tries to marry Cat.