Self-Demonstrating Song

"That song had no content! It wasn't even about the movie, it was about itself! That's like breaking the ninth wall!"

—Jed, Commentary! The Musical

An entire song (or sometimes just a single line of the lyrics) which deliberately provides an example of whatever the subject is, usually for comedic effect.

Compare I Resemble That Remark, This Is a Song, Heavy Meta , Trope Name, and Boastful Rap (as most of that features this trope).

Examples of Self-Demonstrating Song include:

Live Action TV

• The lyrics to the theme song for It's Gary Shandling's Show are about how the songwriter is writing the theme to It's Gary Shandling's Show.

Music

• "25 or 6 to 4" - Chicago's breakout song, one of the founders of 70's rock and considered to this day to be one of the greatest songs ever written is about... Not having anything to write about. No, seriously, that's it. People have been trying to find a deeper meaning in it for decades (ranging from drugs to sex to The Vietnam War), but just give up people, it's really about nothing.
• "Dance Stop" by Daniel Amos is about society doing its best to ignore a nuclear apocalypse, dancing right until the bombs detonate. The music is fast and upbeat, and DA would encourage fans at concerts to dance along.
• "Superpowers" by Five Iron Frenzy:

Sometimes we have a deadline, for writing our songs.
Five minutes left to write this one... la, la la, la la, la la la.

• "Headphones" by Jars of Clay. The lyrics are about isolating yourself from other people's problems by listening to pop music. The music is exactly the sort of pleasant pop sound that the narrator would listen to.
• Lou Reed's "Walk on the Wild Side"

And the colored girls go "do, do-do, do-do, do-do-do-do"

• Bowling for Soup's "A Really Cool Dance Song," which is a techno dance song in which the singer explains that in order to make money, they're doing a techno dance song.
• "Song Inside My Head" by The Arrogant Worms. The song is about an Ear Worm and it IS an Ear Worm. Chances are, like the song's protagonist, you'll have it stuck in your head whether you like it or not.
• "This is the song that doesn't end, it just goes on and on my friends. . ."
• Weird Al's "(This song's just) six words long."
• "School's Out" by Alice Cooper:

Well, we've got no class
And we've got no innocence
And we've got no principles
We can't even think of a word that rhymes!

• Bad Religion: "Cease". Final lines:

What pretension! Everlasting Peace
Everything must <Abrupt cutoff. CD ends.>

• "Move" by John Reuben:

'Cause nowadays, music's too political
And maybe just a bit too predictable
The repetition <click>
repetition <click>
repetition <click>
Man, I'm just kidding, or am I?

• Blues Traveler, "Hook":

It doesn't matter what I sa-ay-ay \ As long as I sing with infle-ection,
That makes you feel that I con-vey-ay \ Some inner truth or vast reflec-tion.
But I've said nothing so far-ar-ar, \ And I can keep it up as long as it takes!
And it don't matter who you ar-ar-are,
If I'm doing my job, it's your resolve that breaks! Because
the hook brings you back, I ain't tellin' you no li-ie!
The hook brings you back, on that you can rely-ay-ay-ayayay!

• DaVinci's Notebook, "Title Of The Song".
• The first verse of Leonard Cohen's "Hallelujah" is about its own chord sequence.

It goes like this: the fourth, the fifth
The minor fall, the major lift

• Mitch Benn is fond of this; for example, "Boy Band", "West End Musical" and "The Apathy Song".
• "Body Be" by Johnny Q. Public explores the idea that believers in Christ can be different, while still members of one spiritual body, and that if one part tries to intrude on the natural function of another, chaos ensues. Around the bridge another song begins, then fades out. It comes back near the crescendo and the entire song dissolves into a confused mess.
• Subverted or Averted (Depending on your opinion) in the song The Sultans of Swing by Dire Straits. Many genres of music are listed in the Sultans' repertoire, and the song itself does not belong to any of them.
• "Three Minute Positive Not Too Country Up-Tempo Love Song" by Alan Jackson.
• The famous Gaita song "La gaita onomatopéyica", lit.: "The onomatopeic Gaita". No points for guessing what the lyrics are.

Theater

• Spamalot's "The Song that Goes Like This".

Web Original

• "Ten Dollar Solo" from Commentary! The Musical is entirely about itself.
• Tobuscus Dramatic Song is an emotional-sounding song... as long as you don't speak English. The lyrics simply explain the fact that he's not singing about anything serious or dramatic but it just sounds like that, all whilst lampshading the music, vocals and how foreign people who don't speak English might find this song intense. See it here.

Western Animation

• The song "Montage" from South Park (and later, Team America: World Police) facilitates this trope by describing the exact narrative devices and reasoning behind Montages while the viewer actually watches a montage on-screen.
• In the Barbie Princess and the Pauper movie, the pauper-turned-princess and her etiquette master have a song detailing what a princess must do. One of the pieces of advice is "always harmonize in thirds". Guess what they do on that line.