Proto-Sylvester (simply known as: Prototype-Sylvester) is a character from the Looney Tunes and Merrie Melodies series. Although its appearance varies, it is commonly seen with black and white fur (similar to its official successor Sylvester).
In The Cagey Canary, a Cat tries to catch a Canary, but he is stopped by Granny and she threatens to throw him out in the rain. After many re-tricks, he fails. Finally the Cat is out in the rain with the Canary. This is the only cartoon where proto-Sylvester has brown fur instead of black and white fur.
- In the episode "The Fifth-Column Mouse", mice defeat Proto-Sylvester in the same style as Sniffles did in "Naughty but Mice".
- In the last two Tweety cartoons directed by Bob Clampett ("Birdy and the Beast" and "A Gruesome Twosome") there is a similar cat character to Proto-Sylvester known as Schnooks.