Cat R. Waul was the chief antagonist of An American Tail: Fievel Goes West, the first sequel to the classic American Tail. Cat R. Waul was a devious but ingenious feline criminal, who pretended to be the champion of a "brave new world" where cats and mice would co-exist while secretly plotting to turn the mice into "mouse burgers" once they had outlived their usefulness to him in building a town in the Old West. Like the villainous Warren T. Rat before him Cat R Waul was defeated by an older Fievel, who teamed up with his old friend, Tiger, and the reluctant former Sheriff Wily Burp in order to drive Cat R. Waul and his band of outlaws out of town for good.
Cat R. Waul was a gentleman by nature, yet underneath his civilised exterior lay a violent streak and the natural predatory instincts of a feline- he had a way with words and refrained from violence unless it was in his favor but would deal with any threats to his plans with ruthless efficency. He held the law in little regard and saw himself as superior to almost everyone, making him rather arrogant as a result.
Cat R. Waul had a softer side to his nature, however, as he was geniunely fascinated with Tanya (Fievel's sister) and her singing voice to the point of putting her on stage, despite the initial hostility of the other patrons over having a mouse performing.
Cat R. Waul was served by a number of feline thugs who lacked his "level of sophistication", yet helped him in their own ways, such as when he ordered them to attack the mice sector of New York in order to drive the mice underground and - via the use of a puppet - trick them into buying tickets out West to a "safer world": he also had a henchman in the form of T. R. Chula, the tarantula, who had a sadistic streak even for a spider.
Cat R. Waul's genius was shown in the way he designed a giant mouse-trap with the intent of gathering all the mice who had helped build the town onto it in the guise of a stage only to kill them; however, Fievel, Wily Burp and Tiger showed up and foiled this plan: in the resulting battle, Cat R. Waul and his entire gang were catapulted (literally) out of the town via this mouse-trap device.
After his defeat, Cat R. Waul would return as a recurring enemy in the animated series American Tails, which was a short-lived series based on the movie.