Chorrosive is a simple device: it accepts audio in, runs it through various types of battery acid, and drops it out the other side. Nice.
The aforementioned 'Battery Acid' is comprised of a chorus unit, band pass filter and transistor emulation, applied to the incoming audio in varying degrees. Common usage is via the Large Friendly Dial on the front. Turn it up to stir the acid; turn it down to retrieve your original signal.
Freeware by BetabugsAudio