Over 25 years ago, Slipknot, who hadn't even released their debut album yet, played their first-ever Ozzfest show — a seven-song set of absolute fury.

The hell-raising event's 1999 excursion launched on May 27, bringing some of metal's most premiere acts, up-and-comers and hopeful unknowns on a long road through the U.S. and Canada, wrapping up at the end of July.

Billed quite low were a brand new band from Iowa, who took their first major steps in changing metal forever.

Below, view Slipknot's setlist from their Ozzfest debut, see who else played that year and read reflections from Shawn 'Clown' Crahan about the whole experience.

Ozzfest's 1999 Main Stage

Black Sabbath
Rob Zombie
Deftones
Slayer
Primus ft. Buckethead
System of a Down
Godsmack

Ozzfest 1999 Second Stage

Drain STH
Fear Factory
Static-X
Hed PE
Pushmonkey
Slipknot
Puya
Flashpoint
Apartment 26

Clown: "We Went Hard That Summer"

For Slipknot, the exposure to large crowds resulting in immediate validation that their visual and musical vision was a force never before seen in metal.

In an oral history of Ozzfest, published by Billboard, founder Clown recalls, "Slipknot was just starting out, and after practices we would watch that little VHS video tape they put out of the first year [The Ozzfest: Live] that had Earth Crisis, Coal Chamber, Neurosis, Slayer, a bunch of the bands. We’re practicing, practicing, practicing, we’re watching the tape over and over and over, just dreaming: “Wouldn’t it be cool if one day we could be accepted, and people liked us? We could be on this festival, we could play, and then, you know, go watch Earth Crisis!”

Ozzfest 1996: Live

"We owe the Osbournes a lot," he continues, "They launched us. Because we were nothing. So we had to go out there and prove it. But the thing with us is when we’re together and we’re onstage, it’s us against everybody. Six songs, 25 minutes, we went hard that summer." While Slipknot played seven songs at the Ozzfest opener, their set was mostly comprised of six songs for the remainder of the run. Some of the band's most enduring songs, such as "(sic)," "Wait and Bleed" and "Surfacing" were performed onstage that day.

READ MORE: The Most Played Song Live Off Every Slipknot Album

As for how hard Slipknot went onstage, Crahan also tells Billboard, "I cut my head open onstage. I cut it on a mic stand – it’s a long story. I was totally unconscious, and they pulled me down the ramp and tried to take me away in an ambulance. I was like, 'Hold on, I wanna watch the rest of ‘Wait and Bleed.’' And I just kept telling the ambulance people, 'Look at that band!' I’m watching my band play, and they’re f–king out of control. They didn’t even know I was gone!"

Read the entire oral history of Ozzfest feature here. View Slipknot's first-ever Ozzfest setlist below and see footage from their 199 debut at the historic metal festival.

Slipknot Setlist — May 27, 1999 (First-Ever Ozzfest Show)

"(sic)"
"Eyeless"
"Wait and Bleed"
"Liberate"
"Surfacing"
"Purity"
"Eeyore

via setlist.fm

WATCH: Slipknot's First-Ever Ozzfest Show

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