I used beepbox for the hell of it (for the main synths), and then I did some mixing in audacity, adding a spoopy zombie moan with a little help from paulstretching, applying a phaser to parts of it.
As for the structure, I did a simple free form scale for the first part, shifting to a gypsy minor scale, then to an "enigmatic" scale, and then to a "Blues scale," (according to beepbox), all in the key of C, because I can. Just wanted to provide an obligatory spoopy song for Halloween before I forget.