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 . The plot revolves around an oil swindle in a South American country. The film was made 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.