Invisible Opponent (German: Unsichtbare Gegner) is a 1933 German-Austrian drama film directed by Rudolph Cartier and starring Gerda Maurus, Paul Hartmann, and Oskar Homolka. The film's sets were designed by the art director Erwin Scharf. The plot revolves around an oil swindle in a South American country. The film was made at the Sievering Studios in Vienna. The critics were not generally impressed with the film, the Deutsche Allgemeine Zeitung described it as "unbelievable and unbelievably awful picture".A separate French-language version The Oil Sharks was also released.