Everyone knows that Slipknot's second effort Iowa was the furthest thing from a "sophomore slump." After breaking into the scene with their debut album in 1999, a tsunami of pressure was coming for the band as they got back into the studio to work on their next release. They were now superstars, and it happened quickly and unexpectedly.

It doesn't take a rocket scientist or a music theorist to point out that Iowa is the Knot's darkest, angriest and heaviest work of art to date. It's typically the top pick among the Maggots, who have been feeding off the sinister mood of the songs for the last 18 years.

The Nine were in absolute terrible shape, both mentally and physically. They had more money in their bank accounts, which fueled their drug and alcohol addictions. The quickly growing level of recognition that followed the release of their debut forced them into pits of depression and anxiety, which further provoked their substance dependence.

Though Vol. 3: The Subliminal Verses would go on to reach No. 2 on the Billboard 200 and All Hope Is Gone, .5 The Gray Chapter and We Are Not Your Kind would peak at the very top of the chart, there will only ever be one masterpiece as disastrously incredible as Iowa. In honor of the album's 18th anniversary, here are 10 facts you may not have known (unless you are a die-hard Maggot).

1. Fuckin' lyrics.

The word "fuck" appears approximately 38 times throughout all of the songs on the album.  Hey, we told you it was angry.

2. All hail the goat.

The 2001 album cover depicts an animated goat head, but the 2011 anniversary edition features an actual photo of the side of the goat's head resting on nails against a wooden wall. The artwork is credited to Shawn "Clown" Crahan — we don't know where he got a dead goat from, and we're not sure we want to.

The album was offered for free by several record stores in the U.K. in 2001 to customers who brought a live goat with them. Probably best to shield their eyes from the album cover.

3. It ruled the charts.

As heavy as it is, the Knot's second work debuted in the Top 10 of the charts in nine countries and peaked at No. 3 in the U.S. It's since been certified platinum in the U.S., U.K. and Canada.

4. Tragedy nearly made it flop.

Iowa came out Aug. 28, 2001. While it did sell initially, tragedy struck the U.S. when the events of 9/11 happened just a few weeks later. The country went into shock, and understandably, many people weren't focused on music.

"What people don’t realize is that as popular as Iowa was, that album didn’t sell. That album didn’t sell at all after 9/11," Corey Taylor told The Ringer. "We all kind of felt, if you were a heavy band, you felt the heat of what happened with 9/11. So not only were you unable to mourn with your country for what had happened, but now it’s like, 'Jesus Christ, what do we do?'"

Eventually, the momentum picked back up and people even began finding solace in the catharsis the album brought them.

5. There were 666 lucky Maggots prior to its release.

A few months before the album came out, Slipknot offered a one-track CD featuring "The Heretic Anthem" for free to the first 666 people who went to Roadrunner's website when the contest was announced.

6. Producer Ross Robinson was broken before production.

Like, literally. Right before production was about to start, Ross Robinson endured an accident on his dirt bike and broke his back. But it didn't stop him, he channeled his physical pain into the making of the album as the band used their emotional pain. They don't call him the "Godfather of nu-metal" for nothing.

7. Corey Taylor physically hurt himself in the studio, on purpose.

There are dedicated frontmen, and then there is Corey Taylor. The singer wanted to inflict pain on himself in order to deliver the most brutal, intense vocal performance that he possibly could. During the recording of the self-titled track, he undressed in the vocal booth, cut himself with a broken candle and made himself vomit.

Don't ever say he didn't give it his all.

8. Sid Wilson's emotional breakdown on (515). 

Sid Wilson's grandfather passed away while the band were in the studio, and he wasn't able to attend the services. He went in to record the opening track (515), and had an emotional breakdown. Clown told Revolver, "I come in the next day, Ross is weeping. Puts his arms around me. 'I've been waiting for you, Clown. You're one of the few people that's gonna understand this. This is my favorite part of the record. It's the realest part of the record.'"

9. The history of "Gently."

Clown actually wrote the song prior to Slipknot, and it first appeared on their debut release Mate. Feed. Kill. Repeat. Taylor altered the lyrics slightly when the band re-recorded it for Iowa by taking a few phrases out.

10. It got Stone Sour back together.

The members of Slipknot still reflect on the making of Iowa to this day, citing how much they couldn't stand each other during that time. Everyone was experiencing so many different personal atrocities that they were at each others' throats. So, Corey Taylor decided to get back with Stone Sour, who had called it quits in 1997, and Jim Root joined him.

"There was a lot of screaming and a lot of animosity, and that's one of the big reasons we went and [restarted] Stone Sour. We had to get the f*ck away. And I realized I had been giving up too much power, too much control. So when we did Stone Sour, I did a lot of the production and arranging, which was good for my head, but it didn't fix the problem," Taylor told Revolver.

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