Sly Sludge is a pollutionist/con man who specialises in tricking others into thinking he and his crew are helping to build something to help the environment just so he can get free space to dump his wastes (oil, toxic sludge, and gunk). Sly and his dumping crew do not seem to have any real reason for doing this—one would assume he is building dumps to make money, but he is never shown collecting any money, however it has been stated that "he'll pollute anything for a buck".