In "Tropic Thunder," Robert Downey Jr. plays the character Kirk Lazarus, a highly acclaimed Australian method actor. Lazarus is known for his intense preparation for roles, and in the film, he undergoes a controversial procedure to darken his skin for a portrayal of a Black character in a Vietnam War film. His character satirizes Hollywood's approach to race and method acting, leading to comedic and thought-provoking moments throughout the movie.

"Tropic Thunder" is not set in Vietnam; rather, it parodies the Vietnam War film genre. The story follows a group of actors filming a war movie in a remote jungle, where they inadvertently become involved in real-life conflict with a drug cartel. While the film draws inspiration from Vietnam War movies, it is primarily a satirical take on Hollywood, filmmaking, and the experiences of actors. The setting serves as a backdrop for the comedic and action-packed narrative rather than a direct representation of Vietnam itself.

Yes, "Tropic Thunder" was a commercial and critical success. Released in 2008, the film grossed over $188 million worldwide against a budget of approximately $92 million. It received positive reviews for its satirical take on Hollywood and its performances, particularly that of Robert Downey Jr., who earned an Academy Award nomination for his role. The film has since gained a cult following and is praised for its comedic elements and commentary on the film industry.

Tobey Maguire does not appear in "Tropic Thunder." However, he is mentioned in a humorous context during the film. The character Kirk Lazarus, played by Robert Downey Jr., refers to a fictional situation involving Maguire to emphasize his own commitment to method acting. This reference adds to the film's satirical take on Hollywood and the extremes actors go to for their roles. The actual cast of "Tropic Thunder" includes actors like Ben Stiller, Jack Black, and Robert Downey Jr., but not Tobey Maguire.