Dubstep has so far had its ups-and-downs in the electronic dance music world, crawling back from the mid-2000's, to finding itself on main stages at the worlds largest bass festivals. The sound has been everything from heralded to dismissed during the same time frame. This most likely has to do with the super heavy metallic sounding synths at the core of the genre with many robotic sound designs showing through Skrillex's productions.
This robotic sound caught the ear of Hollywood Composer, Steven Jablonsky, which led to Skrillex being called into the studio to produce the robotic sound designs for the movie. This collaboration was highlighted in the Documentary about making the film titled, ‘Transformers 4: The Final Touches. Check it out below!
Skip ahead to 13:30 in the video to watch Skrillex's production.