Over processing usually leaves you with audio that lacks it original luster, or perhaps it starts to sound like the processor itself. However, sometimes you might end up with something interesting as a result of pushing the processing beyond the normal boundaries. While listening to the garbled piano in the last entry I could hear something haunting about the passage, so I decided that I would try to bring out those haunting characteristics by adding some unrestrained processing to the recording. I started by reversing it and pitching it down a couple of semitones. This brought out a brief harmonic minor melody. Later, after applying some extreme filtering and massive reverb I ended up with this thin, distant, and haunting sequence.
Mangled, Reversed, Distant, and Filtered Piano
To generate this pattern I loaded a basic 
There are so many ways to use processing to make scary sounds that it’s almost too easy. The classic reverse reverb in the original Poltergeist comes to mind. This example is a recording of a conversation with a colleague during a lunch break at a busy sandwich joint. It’s been reversed, pitched down significantly, run through a low pass filter, slowly phased, filter delayed and run through a long reverb. All this processing has diffused the voices into a hellish ambient drone. 
I came across this old late night session of sleepy Rhodes melodies and decided to render about fifty eight seconds of it. It was originally recorded on November 3, 2006 at about 12:53am. I love electronic timestamps. 
Absolutely nothing is distinguishable in these samples after all the processing that has been applied. My goal was to make a sequence of random samples sound as nasty as possible by applying down sampling, bit reduction, and distortion, then bring it back into something tolerable by applying some resonance filters and reverberation.