It's no wonder that the traditionalists of late 1960s Brazil hated the tropicalia movement. A trippy mashup of psychedelic rock 'n' roll (both the British and American versions) and Latin sounds and rhythms, with elements of beat poetry, jazz, early electronica and costumed theatricality, tropicalia was a wave created by long-haired young people. And in the '60s, waves created by long-haired young people — be they cultural, social or political — were automatically considered threats.

So those who resented the westernization of Brazilian music referred to the movement derisively as iê-iê-iê (yeah yeah yeah).

And the tropicalismos spoke out against the oppressive military regime that had taken over their country in a 1964 junta. This made the Brazilian government very, very nervous.

Perhaps the most culturally significant of the tropicalia bands was Os Mutantes ("The Mutants"), consisting (initially) of singer/guitarist Sergio Dias Baptista, his bassist/singer brother Arnaldo and lead vocalist Rita Lee (who also played the theremin, that freaky sci-fi electronic wave-pattern instrument).

Os Mutantes' music was wild, colorful, celebratory, beautifully unpredictable. It's also no wonder that expressive contemporary artists like Beck, David Byrne, and of Montreal's Kevin Barnes cite the band as a major influence.

Beck, in fact, once described hearing Os Mutantes for the first time as "one of those revelatory moments you live for as a musician, when you find something that you have been wanting to hear for years but never thought existed.

"I made records like Odelay because there was a certain sound and sensibility that I wanted to achieve," he continued. "And it was eerie to find that they had already done it 30 years ago, in a totally shocking but beautiful and satisfying way."

Since 2006, Sergio Dias (as he is professionally known) has fronted a different lineup of Os Mutantes — and it's this version that will appear Nov. 20 at Dollhouse Productions, touring behind the all-new Fool Metal Jack album, supported by the most excellent Brazilian rock trio Capsula.

Are we looking at Savannah's Show of the Year for 2013? Iê-Iê-Iê!

Sergio, what are you doing in Las Vegas? What a weird place.

Sergio Dias: [laughing] Well, if you think about my life, and the history of tropicalia ... have you ever walked on the Strip? It is a total kaleidoscope of craziness. Stupidity, nonsense, fantastic. But that's not really what caught me here. I was here when we were nominated for the Latin Grammy. I never thought about putting my foot on Vegas.

I used to live like 10 years in Manhattan. And I was driving all over the U.S. Never got interested in Vegas. I don't drink, I don't gamble or anything. When we stepped out of the plane, arriving specially, and saw the beauty of the nature ... the mountains just really blew my mind.

They keep on changing, the colors, and the energy here is so extremely magical, you can feel the entities of the Shoshones and the Navajos and all this, they're alive here. And then you go 30 miles and you're at Lake Mead, which blows your head off. You get a little boat and you go out there; there's nothing better to feel than this.

Then you go another 30 miles and you're in a ski resort with, like, snow! It is an amazing place. And strategically, it's so close to everything. You guys have the best roads, and the best cars. Enjoy the ride, and in three hours you're in L.A. or whatever.

Living here is so good compared to São Paulo. São Paulo became like a monster of what it was. I think it has like 14 million inhabitants now. Traffic is unbearable. The cars are all grey, black and white. There's no colors. It's all so dirty. And here, it's so good.

You said not long ago that you didn't want to be "part of a dead band." However you look at it, it's been a long time since you started. Are the goals still the same?

Sergio Dias: It's very simple: I never look back. I look forward, and that's the most important thing in life. If I were to be playing "Satisfaction" until the rest of my days, you know, that would be a pain in the neck. That wouldn't make any sense for me.

I remember that we were playing here in Vegas at the Hard Rock Café, and the same night was the Rolling Stones, playing somewhere else. We had a new record out. I'm 62, OK, Jagger is older than me, but why the hell don't they make new material?

I wish they did, because I'm a fan. The guys are living, they're musicians and composers ... this is a living thing, you know, it's a living entity. That's why we keep on doing Os Mutantes.

I can't understand a band that exists and don't produce. Don't care any more.

Honest truth, though, isn't that what people want from them now?

Sergio Dias: I don't think so. McCartney, at least, he's putting out a few things. We might like it, we might not like it, but that's how it is to be an artist. You have to put your face to be slapped or not. Because otherwise, why are you doing that? They don't need to do that for the money, so why? I don't understand, honestly.

There was a Rolling Stones concert televised in Brazil, and I remember seeing Ron Wood, he had a solo. It was a typical, silly, silly blues thing or whatever. And I saw that he wasn't there, man. I felt so embarrassed. I turned it off immediately.

Because for me, as a guitar player, there's always something new to do, you know? I don't want to criticize them in any aspect, definitely. Maybe he had a bad day that day.

It was a very hard thing to feel, as a co-musician. Because we understand this — we know what it is to be stale. This is awful. It's just the worst thing that can happen to a musician or artist.

At 16 in São Paulo, with all that was happening, weren't the reasons for making music different?

Sergio Dias: No, I don't think so. I think I probably am an anarchist in my own soul, you know? Never let your inner children die. If you do that, man, you get old. I think I'm younger for longer.

I always love to see what's gonna happen. It's like taking a drive — "What's gonna be after the next mountain?" Always, there's something new. Sometimes it's boring; sometimes it's 800 miles, nothing happens, but then suddenly you find such a great valley. You have to be patient, you have to believe and you have to trust that you're going to somewhere special. Always.

Are you still enjoying it? Are you still having fun?

Sergio Dias: Yeah! If I wasn't having fun, you wouldn't be talking to me now. I would be retired, doing something else, honestly because there's no way that I would be doing this. I leave tomorrow on this new tour. It's hard, man — I have a slipped vertebrae, I hurt my back, and I have to go for hours and hours sitting in this bloody van and all this stuff.

But we have so much fun in the band! You have no idea how much fun we have on the tour.