Tropic Thunder is a movie.
Justin Theroux . He is also known as a screenwriter for films such as Tropic Thunder , Iron Man 2 , Rock of Ages , and Zoolander 2 . Tropic Thunder . It was written by Stiller , Justin Theroux and Etan Cohen . The film received generally positive reviews , with critics praising the film 's characters , story , faux trailers , and the performances of Stiller , Downey , and Tom Cruise , though the depiction of the mentally handicapped proved controversial .