From Wikipedia: ”Spooky" was originally an instrumental song performed by saxophonist Mike Sharpe (Shapiro), written by Shapiro and Harry Middlebrooks, Jr., which first charted in 1967 hitting #57 on the US pop charts. Its best known version was created by The Classics IV when guitarist James Cobb and producer Buddy Buie added lyrics centering on a “spooky little girl”. In 1968, the vocal version of the song reached #3 in the U.S. (Billboard Hot 100) and #46 in the UK.
Cobb (along with bandmates Robert Nix and Dean Daughtry) later became part of the Atlanta Rhythm Section and re-recorded “Spooky” in 1979. ARS’s version hit #17 in the US and #48 in the UK.