Elements of a horror musical song?
When composing horror music for musical drama in general, what does one need to consider as in harmony, melody and rhythm, etc.? For harmony, I am especially interested in what chords are normally used as the root, what chord progressions are common and what special chords(all types of diminished, etc.) are typically used. For melody, I am particularly interested in what scales are normally used to compose the melody (including non-traditional scales such as various pentatonic scales, etc.). Lastly, for rhythm, I am curious about whether any particular form of rhythm is common and what meter is common.