Iron Butterfly
Iron Butterfly is an American psychedelic rock band best known for the 1968 hit "In-A-Gadda-Da-Vida." Their heyday was the late 1960s, but the band has been reincarnated with various members. In-A-Gadda-Da-Vida is among the world's 40 best-selling albums, selling more than 30 million copies.
source: Wikipedia