For millions around the world, the theme from M*A*S*H (Mobile Army Surgical Hospital) brings back warm memories of their favorite show. In its day the comedy-drama scaled the heights of TV ratings.

But what viewers may not realize is that behind the comforting tune is dark subject matter with an unconventional source.

The actual title of the track, composed by Johnny Mandel, isn’t M*A*S*H – it’s “Suicide Is Painless”. It also had lyrics, which is where the really surprising thing comes in. Because those words were written by a 15 year old!

Michael Altman was the teenage son of Robert Altman, who directed the original movie of M*A*S*H in 1970 (based on a novel by Richard Hooker).

This in turn inspired the show, which was created after a big screen sequel fell through. Before his death in 2006, Altman Sr. was regarded as a true maverick filmmaker. M*A*S*H suited his offbeat sensibilities perfectly.

Nowhere is this more apparent than in the famous “Last Supper” scene, for which the song was written. Captain “Painless Pole” Waldowski (John Schuck) was the crestfallen camp dentist looking to end it all. So his colleagues decided to throw a mock funeral in his honor.

As sung by the character of Private Seidman (Ken Prymus), “Suicide Is Painless” hit home, and Waldowski chose life after the performance. The title comes from the fact the tortured tooth-puller planned to do the deed with a sleeping pill.

“Bob and I were sitting around getting rather ripped one night,” Johnny Mandel revealed to Jazzwax.com in 2008. “Bob said to me, ‘You know, I need a song for the film. It’s that Last Supper scene… It’s got to be the stupidest song ever written.’ I said to myself, ‘Well I can do stupid.’”

The helmer tried to write lyrics for the dubious ditty himself, but claimed he couldn’t think of something stupid enough. According to Mandel, Altman’s next words were perhaps the ultimate back-handed compliment: “All is not lost. I’ve got a 15-year-old kid who’s a total idiot.” Young Michael reportedly wrote the lyrics in five minutes.

The kid had the last laugh, as Suicide Is Painless went on to become a classic. It’s ranked #66 on AFI (American Film Institute)’s 100 Years… 100 Songs, and has been covered by such diverse acts as Burt Bacharach, Marilyn Manson and Manic Street Preachers.

In 1980 it topped the UK Singles Chart and was in the Top 10 as recently as 1992. Best of all Michael received over $1 million in royalties, dwarfing his father’s $75,000 directing fee.

This must have especially stung due to it being Altman’s idea to make Suicide Is Painless the theme. Mandel wasn’t a fan of the move.

“You have these army medic helicopters flying in a war zone with this soft melody playing,” he said. “It felt odd.” But the Altmans’ gamble paid off. The stark contrast became a feature of both the big and small screen versions of M*A*S*H, finding humor in the horror of the Korean War.

When the characters reached TV screens, rule-breaking surgeon Hawkeye Pierce transformed from Donald Sutherland to Alan Alda.

Elliott Gould was replaced by Wayne Rogers as “Trapper” John McIntyre. The result was a huge success, though Robert Altman disapproved, thinking they oversimplified the premise.

As spoken on the M*A*S*H DVD commentary and reported by The Dallas Morning News in 2002, he believed “it was the antithesis of what we were trying to do.

But most people don’t even know this movie exists. If you poll the world, they’d say, ‘Oh, that was that series with Alan Albert,’ or whatever his name was.”

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Nevertheless, the final episode of the show was the most-watched episode of television in history. Someone may even have said to Altman that this type of thing brings on many changes. And he can take or leave it if he pleases.