with the shimmering oil effect being digitally placed over the actors' corneas in post-production. The crew went through various iterations to find the two "right" types of fluids. According to physical effects crewman David Gauthier, they used a mix of oil and acetone, which he believed gave the substance a more globular look. Special effects technician Mat Beck was able to digitally bend the oil effect around the shape of the actors' eyes. The man in the plane in the teaser, Robert Maier, worked as a construction coordinator on the show, and felt that his part in the episode fulfilled a "life-long dream" of working as a stuntman. Nicholas Lea's name was purposely left until the ending credits in order to preserve the sense of surprise. Reception Ratings "Piper Maru" premiered on the Fox network on , and was first broadcast in the United Kingdom on BBC Two on . The episode earned a Nielsen household rating of 10.6 with an 18 share, meaning that roughly of all television-equipped households, and of households watching television, were tuned in to the episode. A total of viewers watched this episode during its original airing. Reviews "Piper Maru" received positive reviews from critics. In an overview of the third season in Entertainment Weekly, the episode was rated an A. The review described "Piper Maru" as featuring "a tough and sentimental Scully", noting that "action-packed detective work by Mulder enhance[s] an already crackling scenario." Reviewer Emily VanDerWerff of The A.V. Club gave the episode an A and wrote positively of the unfolding mythology, noting that the "great thing about "Piper Maru" is that it still belongs to the period of time when the mythology episodes were exposing us to more pieces of the puzzle, fitting in various things that we were meant to incorporate into the whole. This is the first time we meet the black oil, but it's obvious that others know all about it". Critical Myth's John Keegan gave the episode eight out of ten, and complimented the introduction of the black oil, writing "this episode is a good introduction to the black oil virus, providing a bridge from the mythology elements earlier in the season to the larger scope of the conspiracy to be revealed." Nick De Semlyen and James White of Empire named it the sixth "greatest" episode of the series, describing it as "thrilling", "pacey" and "balanced". The introduction