I recorded me strumming a thick rubber strip and changed the pitch and made it sound sort of like drums. I ran it through a plugin called "Throbber" which is like the Gristleizer that Throbbing Gristle used.
You can read about the plugin here:
http://www.audiomastermin d.com/detail-throbber-938 0.html

I also experimented with feedback to give it an echo and make some noise.