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

Siouxsie And The Banshees - Peek-A-Boo
Zappa - Calling any vegetable

Side 2 of Lou Reed's 'Metal Machine Music'.... 

Wow, not one but TWO mentions of Birthday, must say that I screamed the very same when saw the thread title. Hmm, maybe almost as unique as that (now that surely must be an oxymoron!), in second place, silver medal, runner-up...
All Tomorrow’s Parties
The vocal is odd, the organ timing is most odd, the guitar is odd and the drum is just, well, odd. And I love it so dearly for all of those reasons.

Well you have to have Joe Walsh's All night laundromat blues

Audience: Belladonna Moonshine & I had a Dream
Gentle Giant: Free Hand, Proclamation

And not least: Traffic, Walking in the Wind

Great stuff

Karlheinz Stockhausen - Stimmung
https://youtu.be/3hPkJW95jsw