Not since “Fritz the Cat” has an animated film so richly deserved its rating. In fact, it will still come as a great surprise to even the dirtiest and most jaded viewers that “South Park: Bigger, Longer & Uncut” was not rated NC-17 or banned.

Many viewers may find they actually do have limits on how much crudity they can handle. It is amazing to think that “Lolita” couldn’t be shown in the states but “SP:BLU” made it with virtually no trouble.

The movie opens with a surprise. “South Park” is … ready? … a musical. This flick is chock full of songs, some of which are quite rousing, and all of which contain foul language and even more offensive concepts. For example, the second song in the film is titled “Fuck you, uncle-fucker!” and amounts to about 200 ways to insult someone by calling him “uncle-fucker.”

This song is sung by Canadian comedy duo Terrence and Phillip during their premiere film, “Asses of Fire.”

It is also the catalyst for the film’s plot as it corrupts our young heroes who are entranced by the vulgarity. Soon, all of the children of South Park are swearing uncontrollably. This device allows series creators Trey Parker and Matt Stone to go hog wild giving fans what they want: an uncompromised, uncensored and vulgar version of a cult classic cartoon that got its start in animation festivals.

The first 10 minutes of the film show Stan, Kyle, Cartman and Kenny at their filthy-mouthed best giving their teachers, counselors and parents the business in terms that would make a sailor blush. The device gets pushed a bit too far and just as the wild dog of pointlessness is about to overwhelm the audience, it gets choke-chained by the next plot point.

The children are sent for re-education by their counselor, Mr. Mackey, who sings, “Don’t say ass or fuck or shit, m’kay? Don’t call someone an asshole when you can call them a buns-hole, m’kay?”

The plot thickens as the children undo all they have been taught by seeing “Asses of Fire” again. Only this time, Kenny tries to prove to Cartman that it is possible to set a fart on fire. His coat goes up in flames and without revealing too much of the plot, Kenny dies. But only after a special appearance by George Clooney who utters the uproarious line: “We accidently replaced your heart with a bake-potato … you only have three seconds to live.”

This time, drastic measures are required and Terrence and Phillip are arrested when they are set up by Conan O’Brien on “Late Night.”

Stan’s mother becomes the head of a movement to rid the world of the corruption of potty-mouthed Canadians who are a bad influence on the children of America. The Canadians respond by bombing all of the Baldwins in Hollywood.

Meanwhile, in hell, Kenny discovers that Satan and Saddam Hussein are planning to take over the world.

The seventh sign will be the execution of Terrence and Phillip. At that point, the doors of hell will open wide for Satan and Saddam to rule the earth in darkness for a million years.

The scenes of Satan and Saddam discussing their homosexual relationship were some of the sickest scenes ever filmed, and that includes “Ishtar,” “Deepthroat,” and “Faces of Death.” At one point, after two gratuitous penis shots, the lights go out and the audience can actually hear the sound of Saddam penetrating Satan from behind. It was the most disgusting display of gross noises since President Bush threw up in front of the Japanese.

Cheech and Chong movies are mild, family fare by comparison.

Meanwhile, the boys decide to start a resistance movement with the aid of a young French boy whose disgust with God is expressed by referring to the lord as a “faggot.”

After a pitched battle between the Americans and Canadians, Stan makes an impassioned plea for parents to stop looking for scapegoats for their children’s poor behavior and place the blame where it belongs, on the children.

The film manages a happy ending in which the face of Kenny is revealed. Descriptions will be left out for suspense.

This movie is a mass of contradictions. At times, it seems as though it is perched at the point of making the most sublime statements about our culture which are then followed up by five minutes of humor which make junior high school boys with a copy of Juggs look like H.L. Mencken reviewing “Light in August.”

Arguably, no one is going to “South Park” to be enlightened, but, at the same time, it seems like a waste to come so close to great social commentary in an accessible format only to cover it up with fart jokes.

After a while, we get it. There are no limits. You can say “fuck” and “shit” and “cocksucker” and “limp donkey dick” as many times as you want. You can make jokes about German “scheisse videos” all you want but after a while, spewing filth just gets old.

Granted, there is no better excuse to do it if you are being told you can’t. But once the veil of oppression is lifted, give it a rest for the love of God.

The Comedy Central version of “South Park” is ultimately more pointed and funny because of the creative ways in which they get around rules governing swearing on television.

This flick is a laugh riot though, and no “South Park” fans will be disappointed. The comedy stylings of Parker and Stone deserve all due praise here in spite of the new levels of depravity they seem to have descended to.

A word of warning, however. No children should see this movie as it would constitute serious emotional abuse. This is no joke. “Beavis and Butthead” are excellent babysitters compared to “South Park.” You will mess your kids up real good taking them to see this movie.