Fat Freddy's Cat (the animal has no other name) is an orange tabby tomcat nominally belonging to Fat Freddy Freekowtski, one of the Freak Brothers, a trio of hippies who are featured in Gilbert Shelton's underground comix.
The Cat is much smarter than Freddy, and is a sort of hippie Garfield(whom he predates), sharing laziness and gluttony with Garfield. He tends to regard the Freak Brothers with amused contempt, and routinely displays greater intelligence than they do.
While the Cat is usually featured in a small strip below a Freak Brothers strip, he has had independent appearances and storylines of his own. Like Calvin of Calvin and Hobbes, he has a fertile imagination, and one of his storylines featured him playing the role of "F. Frederick Skitty," an undercover agent sworn to stop the distribution of "Hee Hee Hee," a drug that turned people into homosexuals. At another time, one of Fat Freddy's schemes involved trying to replicate Dick Whittington's success by selling the Cat to the (fictional) small, oil-rich nation of Pootweet to deal with mice.