Furrball was the fictional blue alley cat on Tiny Toon Adventures. His mentor and favorite teacher at school was Sylvester the Cat, although the two similarities only seemed to include their appetites. He has a bandage on his tail, and also has a hole on his ear. He was usually depicted as living in a cardboard box in a back alley or as an unwilling pet of Elmyra. He talks very rarely, except for a few typical cat sounds. In contrast to most of the other characters, he generally did not speak and was portrayed as a typical pet character (such as in the Porky Pig and Sylvester cartoons).

Furrball spent much of his time trying unsuccessfully to eat Sweetie Pie, a pink canary; and Lil' Sneezer, a baby mouse with many allergies and hurricane-force sneezes. Some of his misadventures included getting a pair of malfunctioning 3-D glasses glued to his head, being run over by a street-painting truck and then being mistaken for a skunk (immediately leading to pursuit by an amorous Fifi Le Fume), being hypnotized into trying to eat a pit bull for supper, and becoming the host of a family of singing Italian fleas.

Furrball's typical cat sounds were provided by Frank Welker.