Cloaca is a large installation that turns food into feces, allowing artist Wim Delvoye to explore the digestive process. In his large mechanism, food begins at a long, transparent bowl (mouth), travels through a number of machine-like assembly stations, and ends in hard matter which is separated from liquid through a cylinder. Delvoye collects and sells the realistically smelling output.
I saw a couple of Delvoye's Cloacas in a museum years ago (he has built several models, the first using a washing machine as "stomach", if I recall correctly).
I recall reading that the purpose of the work was to show how one can put a lot of effort into something (he really worked on making it as close as possible to physiological human digestion) but in the end the result can be shit.