CHICAGO (CBS) — Rock star Alice Cooper got the full “We’re not worthy” treatment Tuesday night, when he made an in-person appearance to introduce a 25th anniversary screening of the movie “Wayne’s World” in Millennium Park.

Cooper said he didn’t plan a speaking role in the 1992 movie, just a song, but was handed eight pages of script by Michael Myers when he showed up on set — and had 20 minutes to learn it.

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What followed were two raucous takes of improvisation that became “vile” in 10 minutes of outtakes, as Myers and co-star Dana Carvey tried to break him up as cameras rolled, Cooper said. But it also introduced him to a new generation of fans.

Fan girl and baker Johanna Wyss made Cooper a red velvet cake decorated like Cooper’s severed head; a nod to the trademark gore of the Rock and Roll Hall of Famer’s shows, which feature fake guillotinings and gallons of fake blood.

Fan girl and baker Johanna Wyss made this red velvet cake decorated to look like Alice Cooper’s head, and presented it to the glam rocker at Millennium Park on Sept. 6, 2017, as he opened a 25th anniversary screening of “Wayne’s World,” in which he had a cameo appearance. (Credit: Bob Roberts/WBBM)

Cooper called his shows “Rock Vaudeville,” and said Groucho Marx himself described it that way. How many of today’s rock, pop, and rap stars would even know who Groucho Marx was?

“It’s sort of had a very Broadwayish look, but in a very dark way,” he said.

Cooper said he has enjoyed his role as one of rock’s original villains. Indignant parents loved to hate his shows in the 1970s.

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“The Beatles and the Stones were all rock heroes. There were no rock villains. There was absolutely a lot of Peter Pans, and no Captain Hooks, and I just said, ‘Well, I will gladly be Captain Hook. That’s the most fun job in the world,” he said.

Now, Cooper said the joke’s on those same parents.

“Sixteen-year-old kids come with their dads and their granddads,” he said.

What keeps him going after decades of losing his head on stage?

“If you think that you’ve done your best album, or if you think you’ve done your best tour, then you should stop. I don’t think I’ve done my best album yet. I just finished my 27th album, and it’s so much fun, my show is, to do every night that it’d be silly to stop right now,” he said.

At age 69, Cooper said he is having too much fun to call it quits, although he already plays a mean game of golf.

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He has been touring with fellow Rock and Roll Hall of Famers Deep Purple, and they perform Wednesday night in Tinley Park.