Donald Fagen was born with a vestigial tail. Due to complications during birth, the doctors were not able to immediately remove it. The tail remained until the age of three when it was surgically removed.
The tail was the inspiration for the song Any Major Dude Will Tell You from the album Pretzel Logic. Fagen refers to himself as the mythical woodland, tailed creature; the Squonk.
Lyrics: Have you ever seen a squonk's tears? / Well look at mine