The second night of the South Park 25th anniversary shows at the historic Red Rocks Amphitheater in Morrison, Colorado Wednesday night provided plenty of surprises — even, in some cases, for the key figures on stage, not all of whom had been prepped ahead of time about a crowd-rousing musical cameo from two members of Rush.

With an unprecedented number of Kyle, Cartman, Stan and Kenny costumes sprinkled throughout the sold-out crowd, the concert got underway with the co-creators of the Comedy Central animated series (and proud Colorado natives), Trey Parker and Matt Stone, performed a rendition of “Uncle Fucka” that magically brought tears to some of those watching. Despite the expectedly crass lyrics, the song felt more like a ballad, with Parker at the grand piano singing his heart out and Stone on the mic shouting the word “fucka” with the passion of Pavarotti.

Parker explained they’d play some songs from the show and then intersperse the set with the “real music” from Primus and Ween. Primus frontman and bass impresario Les Claypool, always the entertainer, was dressed like he was indeed ready to sail the seas of cheese; all that was missing was a monocle.

After performing “Here Come the Bastards” from 1991’s “Sailing the Seas of Cheese,” the motley crew — including Dean and Gene Ween — soon introduced the evening’s first special guest, Colorado governor Jared Polis, who presented Parker and Stone a proclamation declaring Aug. 22 “South Park Day.” Polis, who called Parker and Stone “true sons of Colorado,” had some “South Park”-friendly comments to read from the proclamation that included a reference to Kanye West and the infamous fish sticks episode as well as a nod to another beloved “South Park” character, Mr.  Hankey, the Christmas Poo.

The entire event, which an AEG Live spokesperson confirmed to Variety was the most money Red Rocks ever spent on production, had an emotional air to it — and it wasn’t just the weed smoke hanging over the venue. Parker wiped tears away on at least one occasion as he talked about “South Park’s” humble beginnings. With Claypool’s help, Parker also told the history of the “South Park” theme song, which Claypool assured the crowd they “didn’t do for the money.” In fact, he joked, they only got paid $74 for the intro (“Last night, it was $72,” Claypool admitted).

But nothing compared to the look on Stone’s face when he realized Claypool and Parker had hoodwinked him into rehearsing the drums for a Rush song for a reason unbeknownst to him. As they explained, Rush is one of Stone’s favorite groups and they wanted to surprise him with a message from singer Geddy Lee and guitarist Alex Lifeson, who appeared on the screen as “South Park” characters. Just seconds later, Lee and Lifeson sauntered onstage to the shock of Stone and the entire audience, then proceeded to play “Closer to the Heart” from the 1977 album “A Farewell to Kings.” A man in the audience could be heard saying, “I’ve never been happier in my life,” summing up the energy bouncing around the giant red rocks that make up the venue. (Pictured above, L-R, are Lifeson, Stone and Lee.)

Trey Parker and Matt Stone perform during South Park The 25th Anniversary Concert at Red Rocks Amphitheatre on August 10, 2022 in Morrison, Colorado. (Photo by Kevin Mazur/Getty Images for Comedy Central)Getty Images for Comedy Central

As people held their breath in hopes of hearing “Tom Sawyer” next (because, duh), the show slowly began to wrap up but not before Parker thanked the Comedy Central animators and executives — and basically anyone who make the long-running show happen — who’d flown in for the performance. After Ween performed an extended version of “Voodoo Lady” and Primus banged out “Too Many Puppies,” the night ended with another “South Park” gem, “Boogers and Cum.” The crowd, of course, roared until they returned for an encore, which turned out to be the “Team America: World Police” anthem “America (Fuck Yeah).”

Comedy Central will air the South Park anniversary special on Saturday, likely with all of the F-bombs scrubbed, but it would be virtually impossible to remove the genuine love and admiration tying Primus, Ween, Rush, Stone and Parker together. Considering Parker and Stone recently signed a $900 million deal renewing “South Park” for six more seasons and committing them to 14 movies on Paramount+, we might just see them in another 25 years.

Matt Stone and Trey Parker perform during South Park The 25th Anniversary Concert at Red Rocks Amphitheatre on August 10, 2022 in Morrison, Colorado. (Photo by Kevin Mazur/Getty Images for Comedy Central)Getty Images for Comedy Central