Play these sounds while handing out candy on Halloween night and you'll have a lot of candy left for yourself.

We take it for granted today, but early movies didn't have any sound except for music. New technology allowed for speech and sounds to be added to a movie, creating a soundtrack. Music is essential to a horror movie, but try to imagine one without scary sounds. Watching a horror movie without any sound won't be the same and probably won't be nearly as scary. The musicians and audio engineers responsible for music and sound effects have unlimited tools at their disposal to make a horror movie truly scary.

One of those instruments is called the 'Apprehension Engine,' built by guitar - maker Tony Duggan - Smith for film composer Mark Korven. The instrument is unlike anything you've seen before, but you've definitely heard its horrifying sounds. Korven's most recent horror hit was 'The Witch.' In the first video above, see how Korven plays the instrument for film scoring and how Duggan - Smith built it. The second video is almost eight minutes of horrifying sounds made by the Apprehension Engine. The third video is part one of a two - part video on the traditional instruments and voices used in 'The Witch' soundtrack. I recommend watching these videos with earbuds or headphones to get the full effect.