“Creepy” music is generally in a minor key; upbeat music is in a major key. Shift something like “When the Saints go Marching In” to a D-minor, and it sounds like a hebraic dirge (which I rather like). Shift horror themes to a major key, and you get this:
The transposed X-Files theme sounds like the intro music to a Japanese educational program, while Nightmare on Elm Street could easily sub as the intro music to a low-rent Hallmark Xmas drama.
(via slate.com)