More than a psychedelic rock band, Os Mutantes was an inventive and experimental group that explored in an irreverent and creative way the fusion of genres of Brazilian pop music with foreign music. This innovative aspect was recorded in his first five albums - Os Mutantes (1968), Mutantes (1969), A Divina Comédia ou Ando Meio Desligado (1970), Jardim Elétrico (1971) and Mutantes e Seus Cometas no País dos Baurets (1972), when the band had its classic formation, composed by Rita Lee and the brothers Arnaldo Baptista and Sérgio Dias.
With The Beatles as the main reference in their influences, the group's origin began in 1964, when brothers Arnaldo Baptista and Cláudio César Dias Baptista formed a band called Wooden Faces. His formation also included Raphael Vilardi and Roberto Loyola. Despite leaving the project early, Cláudio César, Arnaldo's older brother, has a relevant importance in the musical structure of Mutantes. He dedicated himself to the activity of lutier and sound engineer, creating guitars, pedals and effects that marked the experimental music of the Mutantes.
In 1965, Rita Lee and Sérgio joined the group, which changed its name to Six Sided Rockers. After that, it was called O Conjunto and later O´Seis. With this name, the band released a 1966 single on 7'' vinyl with the songs "Suicida" and "Apocalipse". O'Seis had Rita Lee, Arnaldo and Sérgio Baptista, Raphael Vilardi, Maria “Mogguy” Malheiros and Luiz Pastura. O'Seis disbanded and Arnaldo, Rita and Sérgio stayed together to finally be born Os Mutantes. The name was given by Ronnie Von when the trio started to perform, still in 1966, on the TV show “O Pequeno Mundo de Ronnie Von". In the following, the group met maestro Rogério Duprat, known as the arranger of the tropicalista movement. Duprat integrated the Mutantes with the other artists of Tropicália. Highlighting here the recording of the song “Domingo no Parque” With Gilberto Gil, in addition to the band's participation in major Brazilian popular music festivals.
Os Mutantes, the first album, came out in 1968 on the Polydor label. The tracks featured in this work are the songs of other artists, such as "Panis et Circenses" (Gilberto Gil, Caetano Veloso), "A Minha Menina" (Ben Jor) and "Baby" (Caetano Veloso). The second album, more authorial and entitled Mutantes, arrived in 1969 characterized by a more experimental sound. It was A Divina Comédia ou Ando Meio Desligado (1970) that the band spawned its big hit "Ando Meio Desligado". In 1970, Rita Lee released Build Up, her first solo album.
In 1971, the band released Jardim Elétrico with an expanded line-up, with Liminha (bass) and Dinho Leme (drums) as new members. The first phase of Mutantes ended in 1972 with the album Mutantes e Seus Cometas no País dos Baurets, which brought the track “Balada do Louco”, the album's success. This work marks the departure of the band from the Tropicália movement and the move towards progressive rock, and it was also the last with Rita Lee. In that year, 1972, all the members recorded an album at the Studio Eldorado in São Paulo, where there was a 16-channel recording table, the only one available in Brazil at that time. However, the record label Polydor refused to release the album as Mutantes. More interested in launching Rita Lee's solo career, the label put this work in stores as the singer's second solo, entitled Hoje É o Primeiro Dia do Resto da Sua Vida. As a consequence, Rita Lee was expelled from the band.
With only Sérgio Dias from its original formation, the band released in 1974 Tudo Foi Feito pelo Sol. A new work, O A e o Z, was released in 1992. However, the material for this album was recorded in 1973, after Rita Lee left the group. In the year 2000, Tecnicolor came out, an album sung in English, French, Spanish and Portuguese that was recorded in Paris in 1970 with the aim of the band starting a career abroad. However, at the time the project was shelved.