Had recently watched the 1970 Movie and found the following [trivia from IMDB](https://www.imdb.com/title/tt0066026/trivia/

*According to Johnny Mandel and Robert Altman, the film’s famous theme song was intended to be the “stupidest song ever written.” After attempting to write the lyrics himself, Altman said he found it too difficult to write “dumb enough,” and instead gave to the task to his fourteen-year-old son. Mike Altman allegedly wrote the lyrics in five minutes, not even expecting to be paid, since he was the director’s son. He ended up making millions in royalties off the song.

The fourteen-year-old son of director Robert Altman, Mike Altman, wrote the lyrics to the theme song “Suicide is Painless.” Because of its inclusion in the subsequent television series, he continued to get residuals throughout its run and syndication. His father was paid $75,000 for directing, but his son eventually made about $2 million in song royalties, with payments continuing, from first syndication through the present day, as MASH (1972) continues in syndication around the world.