Sylvester James Pussycat Sr (Sylvester) is a cat. Character Sylvester first appeared in the 1945 short Life With Feathers, which was directed by Friz Freleng. Although this was his first official appearance, there was a claim that in Notes to You, there was a prototypical version of him.
Sylvester's trademark is his sloppy, yet stridulating lisp. In his autobiography, That's Not All Folks!, voice actor Mel Blanc stated that Sylvester's voice is based on that of Daffy Duck, plus the even more slobbery lispit gets and minus the post-production speed-up that was done with Daffy's. Daffy's lisp, as well as Sylvester's, were based on the lisp of producer Leon Schlesinger. However, Blanc made no such claim. He said that Daffy's lisp was based on him having a long beak, and that he borrowed the voice for Sylvester. He also pointed out that, minus the lisp, Sylvester's voice was fairly close to his own (a claim that his son Noel Blanc has confirmed). In addition, director Bob Clampett, in a 1970 Funnyworld interview, agreed with Blanc's account concerning Schlesinger.
To emphasize the lisp, as with Daffy's catchphrase "You're desthpicable", Sylvester's trademark exclamation is "Sufferin' succotash!", which is said to be a minced oath of "Suffering Savior". (Daffy also says "Sufferin' succotash!" from time to time.)
Prior to Sylvester's appearance in the cartoons, Blanc voiced a character named Sylvester on The Judy Canova Show using the voice that would eventually become associated with the character. Sylvester's most notable foil is Tweety.