* The use of the raised seventh note. The raised seventh note in the harmonic minor scale creates a sense of tension and instability. This is because the raised seventh note is not part of the major or minor triad, so it doesn't fit in with the rest of the notes in the scale.
* The lack of a perfect fifth. The perfect fifth is an important interval in music because it creates a sense of stability. However, the harmonic minor scale does not have a perfect fifth. This is because the raised seventh note replaces the perfect fifth.
* The presence of the minor second. The minor second is an interval that is often associated with sadness and darkness. The harmonic minor scale contains two minor seconds, which contributes to its dark sound.
These factors all combine to create a scale that sounds dark, mysterious, and even sinister. As a result, the harmonic minor scale is often used in film scores and other music that is meant to convey a sense of danger or unease.