Wikipedia
"N.I.B." is a song released by the British heavy metal band Black Sabbath. It first appeared as the fourth track on the band's 1970 debut album, Black Sabbath. The lyrics are in the first person from the point of view of Lucifer. Lyricist Geezer Butler has said that "the song was about the devil falling in love and totally changing, becoming a good person."
"N.I.B." begins with a bass solo by Geezer Butler, titled "Bassically" on some US releases. It involves the use of wah-wah on his bass and was recorded in one take, as the amp's volume control is audibly turned up before the distorted bass intro of "N.I.B." begins.
The song's main riff (as well Osbourne's vocal delivery) have been noted for their Cream-influenced sound - the song has even been referred to as "the raucous defiling of Cream".