When people think of music from the film, most probably think of the hilarious 'Puttin' on the Ritz' scene, where the Doctor and the Monster sing and dance to the famous song. Instead of filling the whole movie with such musical levity however, Brooks had composer John Morris compose music that drew viewers thoughts back to horror.
Young Frankenstein's main theme is the one of the best pieces of horror movie music ever created. It captures the fear and terror of the scientific experiments committed in films like Frankenstein, or the skewering of nature in The Wolf Man. However it is the melancholic nature of the violin solo that stands out, which wails the pain and loneliness of the monsters in these films. Indeed, when I watched the 1931 Frankenstein I had Morris' theme in my head.
For a film that is constantly subverting its audiences expectations, going for humour over fear, perhaps the greatest rug-pulling comes the score which, even when used in Brooks' film to tame the Monster, never loses its power.