WHAT IS THE MOST UNIQUE SONG THAT YOU HAVE EVER HEARD?

Revolution 9, The Beatles

Valley Girl,  Moon Unit Zappa


As to most "unique" that I actually listen to fairly often. . .

Danko/Manuel,  Drive By Truckers/ Jason Isbell

MacArthur Park, covered by many, Four Tops probably my favorite version

Funeral for a Friend/Love Lies Bleeding, Elton John

Highwayman, the Highwaymen

Two Jimmy Webb compositions on here.  He had a lot of stuff one could fairly call unique.

Madman Fischer- Merry-go-round

The music on Yo  Yo Ma's DVD/ CD of his international band with a gypsyish dancing lady playing a Middle Eastern accordian type instrument, and with lots of esoteric percussion.  The name of the album eludes me.

White Port and Lemon Juice. 

Count me as another who was struck by the strangeness of the Napoleon XIV song, "They're Coming To Take Me Away" in 1966. It was immediately one of my 45 rpm purchases and I played it a lot. So much in fact that my Mom told me, "One more time, and they'll be coming to take YOU away". She wasn't laughing, either.
https://www.youtube.com/watch?v=hnzHtm1jhL4
Steve Z