What song or album is the "final boss" of prog rock?

Actually to make that clearer when I first wrote that the then refered to wad intended to be in reference to Pawn Hearts which is 1971. So still not able to work out how the term final boss applies.

Also Punk Wars is a semi sarcastic joke that inevitably becomes progressively funnier every time it's used.

Not a crowded field once we get past the Mascara Snake and Supertramp.

https://www.youtube.com/watch?v=KVop4nLYpoM

https://vassifer.blogs.com/.a/6a00d8341c18b253ef02a308d9f08f200c-600wi

See "Warm Sporran" by Jethro Tull, prog folk disco:

― Halfway there but for you

well of course it would be from the dee palmer era! :)