Few authors will provide permission to a parodist, even less so if the parody uses obscenity to criticize the original. The cases tend to concentrate their analysis on the third fair use factor, the amount and substantiality of the portion used in relation to the copyrighted work as a whole. But similarity should not be read to allow verbatim taking. In Walt Disney Prod. The parody must also aim its criticism at the original work.
Infringement results if the parody falls stray of the mark.
In the case of Metro Goldwyn Mayer, Inc. v. Showcase Atlanta Co-Op. Although precision in targeting the parody helps the parody to achieve its goal, it should not become a factor eliminating the less skillful parodist. True parody will not always criticize all aspects of an original work. Its humor, by necessity will overflow into related areas just as the original work relies upon mental associations of locale, characterization and time period. Although few persons admit to perusing obscenity an inordinate amount of time is spent defining, outlawing and tracking it down.