10 Things You Might Not Know About South Park

South Park has been a favorite of comedy fans since its broadcast debut in 1997, keeping a permanent seat in internet culture thanks to a slew of quotable catch phrases and delightfully inflammatory conversation pieces. Nevertheless, there are a few things about Trey Parker and Matt Stone’s iconic series—which made its debut 20 years ago today—that you might not know.

1. SOUTH PARK PIONEERED THE WAVE OF “MATURE” TELEVISION.

Making its debut in the summer of 1997, South Park entered the small screen circuit just in time to reap the benefits of the Federal Communications Commission’s latest venture: the TV Parental Guidelines. The rating system went into effect in January of the same year, distinguishing “child friendly” programming from “adult content.” Upon its premiere on August 13, South Park became the first weekly series to earn the “TV-MA” (or “Mature Audiences”) label.

2. MOST OF THE SERIES’S FEMALE CAST MEMBERS PERFORM UNDER PSEUDONYMS.

The wealth of the male characters on South Park are voiced by creators and writers Parker and Stone, but the animated Colorado town’s female population has long owed its lines to a small number of women behind the scenes. The voice actresses principally responsible for this lot have been, at various points, Mona Marshall, April Stewart, Eliza Schneider, and the late Mary Kay Bergman.

Early on in her South Park tenure, Disney and Hanna-Barbera mainstay Bergman was sometimes credited as Shannen Cassidy in order to avoid fallout from the ideological differences between South Park and her family-friendly material. Similarly, Stewart adopted the alias Gracie Lazar for her South Park work, and Schneider (who left the series in 2003) performed as “Blue Girl,” a handle she also utilized in her music career. Only Marshall has been consistently credited without a pseudonym.

3. SEVERAL CELEBRITIES HAVE PLAYED EASY-TO-MISS CAMEOS.

South Park’s preferred use of celebrity guest stars differs quite a bit from that of its animated sitcom brethren, a community that typically aims to “play up” the notability of a visiting voice actor. With a few exceptions, South Park favors hiding any trace of a star’s contribution, relegating big-name guests to little more than animal sounds. Actors as renowned as George Clooney, Jay Leno, and Henry Winkler have provided dog barks, cat purrs, and monster growls, respectively, for the show.

4. ONE NOTABLE FAN REFUSED AN OFFER TO GUEST STAR.

Of course, not all Hollywood stars are game for this caliber of work. Taking note of South Park’s meteoric rise in popularity at the inception of its second season, Jerry Seinfeld contacted creators Parker and Stone to express interest in voicing a character. They offered the comedian the nonspeaking part of “Turkey No. 2” in their Thanksgiving episode, but Seinfeld declined.

5. SOME FAMOUS NAMES HAVE WRITTEN FOR THE SERIES.

Today, Bill Hader and Kristen Schaal are TV comedy stars in their own right. However, while Hader was still appearing on Saturday Night Live, he doubled as a consultant writer and then producer for Parker and Stone’s animated series. Similarly, Schaal spent 2007 working as a consultant writer on South Park, before padding her resume with parts on Flight of the Conchords, The Daily Show, and 30 Rock.

6. A SITCOM LEGEND CONTRIBUTED TO TWO EPISODES OF THE SERIES.

It is hardly a surprise to learn that the daringly controversial Parker and Stone hold great reverence for the king of all politically incorrect sitcoms: All in the Family. As such, the pair’s communal dream came true when Norman Lear, the brain behind the groundbreaking series, brought his talents to the South Park set as a writing consultant on the consecutive season 7 episodes “Cancelled” (the 100th episode produced) and “I’m a Little Bit Country.”

7. TREY PARKER APPLIED THE SHOW’S VISUAL STYLE TO A SERIES OF PHILOSOPHICAL SHORTS.

Inheriting a reverence for Buddhism from his father, Randy, Trey Parker went on to discover affection for the philosophies of Zen writer and speaker Alan Watts. In 2007, Parker borrowed the construction paper aesthetic of his popular Comedy Central series to a side project: animated sequences accompanying short segments of Watts’s lectures. Subjects brought to life through Parker’s animation included Watts’ take on music (“Life and Music”), personality extremes (“Prickles and Goo”), and the human race’s relationship with the planet (“Appling”).

8. SOUTH PARK REUNITED A FAMOUS COMIC DUO.

The season four episode “Cherokee Hair Tampons,” which aired in 2000, was notable for employing a pair of guest stars for more than just a few canine grunts. Counterculture comedians Cheech Marin and Tommy Chong, who had long since dissolved their big-screen partnership, both lent their voices to the installment. Chong admitted that he and Marin didn’t record their parts together for the episode, but he did credit South Park with reviving their professional camaraderie.

“Cheech did his bit one day and I came in the next day and did my bit,” he told UCTV. “That was the first time we did something together in 20 years so yes, we can give South Park the credit.” Chong’s math might be a little off—his and Marin’s previous proper film collaboration was Martin Scorsese’s After Hours, although they shared credits well into the ’90s—but the spirit of his words sticks. Since the South Park episode, Chong and Marin have joined forces on a handful of film and television projects, including Cheech & Chong’s Animated Movie.

9. AN INSECT MUTATION WAS NAMED AFTER A SOUTH PARK CHARACTER.

Throughout the first five seasons of South Park, the primary distinguishing characteristic borne by the character Kenny McCormick was his proclivity to die suddenly in every episode. This unfortunate trait won Kenny the honor of lending his name to a mutation in the genetic structure of the adult fruit fly, discovered in 2002 by scientist Sophie Rutschmann. The gene was found to predict imminent mortality upon contact with an otherwise benign strain of bacteria; this “certain death” mutation was aptly nicknamed “Kenny” after South Park’s ill-fated character.

10. THE TOURETTE SYNDROME ASSOCIATION HAS PRAISED SOUTH PARK’S TREATMENT OF THE DISEASE.

Well aware of South Park’s reputation for insensitivity, the Tourette Syndrome Association approached the series’ season 11 episode, “Le Petit Tourette,” prepared to be gravely offended. The nonprofit organization was unsurprised by South Park’s heavy focus on coprolalia, or involuntary cursing—a symptom disproportionately associated with the disease in popular culture—but went on record as saying that they were impressed by the episode’s treatment of the condition, as well as by its wealth of well-researched information.