Based on a character created by underground cartoonist R. Crumb, Fritz the Cat was the first animated feature to receive an X rating, and with all the breasts and penises that pop out during it's scant 78 minute run time, it's easy to see why (in the opening scene, a Rhinoceros construction worker, sitting high atop a scaffold, rises to his feet, whips it out, and proceeds to piss on the head of a poor hippie walking below).
Yet despite it's moments of sex and vulgarity, Fritz the Cat works well as social commentary, throwing a critical light on such late-60's issues as free love, white guilt, police brutality, race riots, drug experimentation and, as we see time and again in Fritz himself, intellectual hypocrisy. At one point, Fritz is hanging out in a pool hall frequented by black crows. While talking to one of the crows, Fritz starts to pontificate on how he feels guilt over the way 'his people' have treated the crow minorities, but when the crow offers to buy him a drink, Fritz turns to the crow bartender and shouts out, “Hey, boy, how about pouring me a drink?”.
The animation style is harsh and gritty, and there are more than a few scenes depicting frank sexuality, yet within the confines of it's shocks and thrills, Fritz the Cat had something very definite to say about American society at the time, and in my opinion, it says it very well.