Iron Butterfly is an American hard rock and psychedelic band, well known for their 1968 hit "In-A-Gadda-Da-Vida". They are considered an early heavy metal band as a result of this song and others like it, as well as the title of their debut album, Heavy. Their heyday was the late 1960s, but the band has been reincarnated several times with various members. VH1 ranks them as number 19 on their list of top 100 "one-hit" wonders.   Wikipedia