"Itchy & Scratchy meet Fritz the Cat" is an episode of The Itchy & Scratchy Show. It is an adult-oriented 1970s-style I&S bootleg cartoon.
From what little of the plot was shown (as the moving images implied that it was going on before Bart and Lisa saw it), Scratchy is attempting to pick up a prostitute when he sees Itchy driving by in a car. When he gets out of the car, Itchy picks up his car and pours gasoline on him (shocking the prostitute) and sets him alight with a cigarette, he then drives off with the prostitute, leaving a burning alive Scratchy shouting "Hey! My threads, baby!". The only known version of the cartoon is a bootleg video that Comic Book Guy owned. It was presumably only available in bootleg form "because of its frank depiction of sex and narcotic consumption".