There is a three note idiom that has appeared in SEVERAL theatrical releases (comedies) recently that indicates danger. I do not know the notes, but it goes "dum dum DUM", and the viewer knows instantly that the scene (or character) is dangerous. There are even sound effect videos of this idiom on YouTube, but they are very short on its etymology. Again, was this composed? Does somebody own rights to this idiom? If not, how did it enter popular culture?
A sample, accompanied by rich viewer commentary, is at http://www.youtube.com/watch?v=bW7Op86ox9g