Rock n' roll lore is filled with successful frontman transplant stories -- AC/DC, Van Halen, Iron Maiden, Journey, King Crimson, Black Sabbath. For a group to switch lead singers mid-ascent, however, is a far more daring trick.

When Faith No More were about to begin work on their third album (The Real Thing, out June 20, 1989) in late 1988, they knew they had plateaued creatively with their original frontman, the late Chuck Mosley.

"Once we finished Introduce Yourself with Chuck, we knew we went as far as we could go with him," explains drummer Mike Bordin. "We knew we had to make a change. And when you know you have to make the change, you just do it. We felt we weren't at the potential that we felt we could be working at and exploring sounds in the manner we should be doing. We had to do it; we had no choice."

"We had been working with Chuck for years and we made two records with him and had gone on a bunch of tours," recalls co-founding member and keyboardist Roddy Bottum. "And bless him; he was an amazing, talented, crazy individual. But his singing chops had a very specific sound. He didn't sing in a traditional way at all. With Chuck, we would have never gotten on pop radio. 'We Care A Lot' the single was probably the height of what we could have expected in that regard."

In search of a new singer, the San Francisco-based funk-metal group began auditioning. But it wasn't until they remembered about a demo tape given to them from a young death metal band from Humboldt County called Mr. Bungle, and guitarist Jim Martin being a particular fan of their singer, Mike Patton.

"We played Humboldt County with Chuck, and Trey [Spruance], the guitar player from Mr. Bungle, gave us their demo cassette," remembers the group's bassist and fellow co-founder Billy Gould. "So we'd play it on the bus, and Jim Martin was really hip to it. So when things didn't work out with Chuck, Jim suggested we reach out to Mike even though we didn't properly meet him yet. We didn't know anything about him other than Jim liked the tape."

"Me and Trey went to see Faith No More in our college where we both went to school at," adds Patton. "They played this little pizza parlor and there were like 30 people there, maybe (laughs). I worked at a record store and we had just gotten We Care A Lot and really liked it. I think Trey liked it more than I did, even. So he was really gung ho about seeing these guys, and we went and saw them and they were totally fantastic. Afterwards, Trey gave them the tape and he said, 'We should just give it to them, why not?' We had a little bit in common with what they were doing, and we thought they just might like it. So we gave them the tape, and they were really cool. We chatted with Bordin for a while, and all he wanted to do was score weed (laughs). But we weren't really into that, which is odd, because this is in Humboldt County."

"Humboldt County is a unique and schizophrenic place," opines Bordin. "I think there's a Twin Peaks vibe up there. But it's beautiful, it's spectacular. Its coastline is rugged and full of redwood trees. And I think it was probably the perfect place for something really weird to incubate, and that was Mr. Bungle."

For the young singer, however, it was unexpected that Faith No More would actual consider him to become their next frontman.

"I got a call at my parents' house from Jim Martin of all people, and he just said, 'Hey man, that tape you gave us is fucking incredible, blah blah blah,' and that was it," Patton remembers. "It wasn't like, 'Join my band!' or anything like that. So I said thanks and that was that. Knowing him afterwards in hindsight, it was the funniest thing that he gravitated towards the Bungle tape more than the other guys. On that cassette, I was just screaming my head off, so maybe that was why."

"It was nothing I would ever listen to, so when the idea came up I was, 'Who is this guy?" questioned Bottum at the time. "I remember listening to the Bungle tape and hearing how great Mike sings, because they would do crazy snippets of covers and it showed a crazy range. But it wasn't my bag."

From there, Patton wouldn't reconnect with them until a couple of years later when he caught Faith No More at The Fillmore in San Francisco in 1987.

"We got the chance to see them opening up for the Chili Peppers, and we drove down," Patton tells Billboard. "Every time we'd go to a cool show in San Francisco, it was like a big event. We always had to figure out whose grandpa's car we were going to borrow, then drive all day, see the show, drive back and go to school the next day. By then, however, Mr. Bungle had a few demo tapes done, and our sound completely changed from the tape Faith No More had. We had gotten very bored of what we were doing, which was like this angular death metal, and had gotten really into Fishbone and the Chili Peppers. So we hired a horn section and changed our whole deal."

In fact, Bordin remembers running into Patton and Spruance again after the concert. And when they informed him how much they had changed since the last demo tape they gave to the group a couple of years ago, they knew they had found their man.

"That's what was immediately beautiful about Mike Patton to us at that point," admits Bordin. "When we played The Fillmore and they came down to see the show, we ran into them accidentally and let them know again how much we enjoyed the tape. And they were like, 'We don't sound like that anymore.' Then the next tape we heard was this super-secret spy ska stuff. That, to me and I think most of us in the band at the time, it carried a lot of weight. Mike was evolving as well. He had such a broad range of music knowledge to be inspired by and draw upon. So he fit in exceptionally well with us, because he was already doing what we were doing on his own exploration."

"More than the music, I really liked the guys," adds Patton. "We all had the same sense of humor and we were all cynical and messed up in the same ways, even though those guys were older than me. But we all could bond over stupid stuff, and obviously music. The funny thing that struck me was The Real Thing didn't really sound so much like the Faith No More I was a fan of, so I think I was a little thrown for a loop on that, but in a good way. It showed me these guys were evolving—they were going somewhere."

Soon after, Patton got the call to try out for the open singer spot in Faith No More.

"They had sent me all these different tapes," Patton tells Billboard. "And they told me they were trying out singers and asked if I wanted to try out. So I was like, 'Why not, it wouldn't kill me.' But my head was in such a different place, because I'd have to take time off school, even though I fucking hated college and the small-town mentality of my area. I just considered it a trip to San Francisco for the weekend, so I took a couple of the Bungle guys with me and made a vacation out of it. And then I went down to play with them and it was really cool. They had tons of material written already. It didn't dawn on me until I was actually doing it that I was auditioning for something."

Once they entered Studio D in Sausalito, Calif. with their producer Matt Wallace, the way these new songs transformed with Patton on the mic superseded their expectations tenfold. The new singer's presence also brought forth a new level of comfort to Faith No More's intersection of dark new wave and heavy metal, leading to a breadth of material that shifted from early rap-metal ("Epic") to synth-driven power pop ("Falling To Pieces," "Underwater Love") to thrash ("Surprise! You're Dead!") to piano bar blues ("Edge of the World") through the course of The Real Thing's 55-minute timeframe.

"He was trying to figure us out at first," recalls Gould. "We were coming from a different world from what he was used to. But he has this key to understanding music on a real gut level, and his ideas honestly made these songs even better."

"It was Patton's first foray into a big studio record," Bottum tells Billboard. "Given where he was coming from as a young man from a small town, he had a lot to prove. And you can hear that on the tracks. You can hear him really working hard in that regard. So all of a sudden he came down and sang these songs we created and we were all just kind of like whoa."

The range by which Patton's vocals opened up the third eye of Faith No More is most prevalent in two of The Real Thing's most intense and transcendent tracks -- the powerful eight-minute title cut and a note-perfect rendition of the Black Sabbath protest anthem "War Pigs." This pair of, well, epics helped to set the stage for the next 30 years during which the band would continue to abandon their funk-metal roots in favor of more eccentric and experimental directions.

"Mike really went places after The Real Thing," admits Bottum with regards to the singer's work both in Faith No More and Mr. Bungle as the '90s rolled into view. "After that record, the whole notion of pleasing people went out the window and we just enjoyed fucking off and doing whatever we wanted."

"Mike made us look at ourselves differently, because we heard his voice and his ideas channeled through our music," recalls Bordin. "And he just opened them up so much. We just let him to his own devices and trust he would do what was right."

Faith No More would go on to record three more albums through their deal with Slash/Reprise, each one more out there than the one which preceded it: 1992's Angel Dust, 1995's King For A Day…Fool For A Lifetime (featuring Spruance of Mr. Bungle on guitar) and 1997's vastly underrated Album of the Year, all classics in their own right. Then, in 2015, they released a comeback LP for the ages in Sol Invictus through Patton's own Ipecac Recordings label (which turns 20 this year). And while the fellas won't directly reveal what to expect in the months to come from the FNM camp, they hint that something is indeed on the horizon to anticipate -- and will no doubt defy the expectations of even their most ardent fans, because it's simply what they love to do even 30 years later.

"We are going to do whatever the hell we want to do," affirms Bordin. "You can call it musical ADD or whatever. But at the time we had been working on The Real Thing, we had both Metallica and Fishbone with classic albums out. Sade released Stronger Than Pride. You go back to that time and you think about an incredibly balanced diet of music. And that's always how we approached music, before Chuck, before Mike, when it was just three guys not cutting their hair and just farting around with music—me, Bill and Roddy. We always did what we wanted to do. There were already enough bands out there, whether it was Whitesnake and Poison, or R.E.M. and Hüsker Dü, or the hardcore scene at the time. The lines were drawn and we didn't really give a shit. And Mike fit into our parameters perfectly."