Word painting / “meta music”

Also I hate to be the one to bring it up but how has Hallelujah not been mentioned. "Well it goes like this" etc.

that's the lyrics describing the music though, not vice versa.

Speaking of blanks, Richard Hell's band leaves gaps in "Blank Generation" where all the blanks go

In "I Bought A Flat Guitar Tutor", 10cc change the chords of the song according to the homonyms of the lyrics (A flat, D 9th, C, B sus, etc.):

I bought a flat
Diminished responsibility
You're de ninth person to see
To be suspended in a seventh
Major catastrophe

The song "One Note Samba" has several of these, wherein the singer refers to the note or notes they're singing in that moment

― Josefa, Tuesday, March 2, 2021 10:26 PM (yesterday)

Not the Jobim song I was thinking of, but "Desafinado" (Br.Por. for "off-key") has a couple moments in the first verse:

Se você disser que eu desafino amor
Saiba que isso em mim provoca imensa dor
Só privilegiados têm ouvido igual ao seu
Eu possuo apenas o que Deus me deu
Se você insiste em classificar
Meu comportamento de anti-musical
Eu mesmo mentindo devo argumentar
Que isto é bossa-nova, que isto é muito natural
O que você não sabe nem sequer pressente
É que os desafinados também têm um coração

...where the bolded words (translated to "off-key", "against the grain" or "crooked") are sung in relative uh... "out-of-keyness" with the song, employing the style of bossa nova which merged classic pop with afro-brazilian samba style.

I'm sure Bill Callahan uses this technique - though the actual songs escape me at the moment. Maybe ones involving trains/planes?

Hard to top that 10cc example, but here are a few others:

Soul Coughing - "Circles" has that circular melody in the chorus ("walk around in circles walk around in circles walk around in")

At the end of "Man in the Mirror", there's a big key change when he sings "make that change". I'm sure there's a whole thread's worth of songs where the lyrics cue a modulation.

In "Despacito" when he sings the title at the beginning of the chorus, the melody slows down and the beat drops out.

A subtler (but really effective) example that I noticed recently is from "WAP": when she says "park you big mack truck..." her voice gets all boomy like, well, a big mack truck

"Everyone loves ascending fourths"

https://www.youtube.com/watch?v=FA3IJOodbWc