The devil's interval.

There is a peculiar musical phenomemon known as a tritone, sometimes called the "devil's interval." It's a sound that supposedly creates a certain dissonance. It shows up in weird places like heavy metal music (Black Sabbath's eponymous song), Bernard Herrman's score for The Day the Earth Stood Still, songs from West Side Story, and incredibly, the theme song for The Simpsons.

One of the two strong dissonances in the diatonic scale, it was called diabolus in musica ("the Devil's interval") by some from the early music era to the baroque period. It was exploited heavily in the Romantic period as an interval of modulation for its ability to evoke a strong reaction by entering the key least related (retaining only two common tones, the least possible) to what occurs previously.

I only barely have any idea what that means. I have a good ear for notes and music. Or I used to when I played guitar. There is a theme from the music for Lost that they play for extremely sad times. I thought it would be played last night for the funerals, but it wasn't. I'm sure it has a tritone in it. I was going to describe it like: ABCDG, with a big gap between the last two notes. I think that's the tritone. Every time I hear this part, I get choked up, I swear. It's the devil at work.