December 1992, he realized the scene opened up the possibility of a film with an older Indiana set in the 1950s. The film could reflect a science fiction 1950s B-movie, with aliens as the plot device. Meanwhile, Spielberg believed he was going to mature as a filmmaker after making the trilogy and felt his role in any future installments would be relegated to that of mere producer. Ford disliked the new angle, telling Lucas, "No way am I being in a Steven Spielberg movie like that." Spielberg himself, who depicted aliens in Close Encounters of the Third Kind and E.T. the Extra-Terrestrial, resisted it. Lucas came up with a story, which Jeb Stuart turned into a script from October 1993 to May 1994. (Stuart had previously written The Fugitive, which starred Ford.) Lucas wanted Indiana to get married, which would allow Henry Jones, Sr. to return, expressing concern over whether his son is happy with what he has accomplished. After he learned that Joseph Stalin was interested in psychic warfare, he decided to have Soviets as the villains and the aliens to have psychic powers. Following Stuart's next draft, Lucas hired Last Crusade writer Jeffrey Boam to write the next three versions, the last of which was completed in March 1996. Three months later, Independence Day was released, and Spielberg told Lucas he would not make another alien invasion film. Lucas decided to focus on the Star Wars prequels. In a 2000 interview, Spielberg said that his children constantly asked when he would make the next Indiana Jones film, and that the project would soon be revived. The same year, Ford, Lucas, Spielberg, Frank Marshall and Kathleen Kennedy met during the American Film Institute's tribute to Ford, and decided they wanted to enjoy the experience of making an Indiana Jones film again. Spielberg also found returning to the series a respite from his many dark films during this period, such as A.I. Artificial Intelligence, Minority Report, and Munich. Lucas convinced Spielberg to use aliens in the plot by saying they were not "extraterrestrials", but "interdimensional", with this concept taking inspiration in the superstring theory. Spielberg and Lucas discussed the central idea of a B-movie involving aliens, and Lucas suggested using the crystal skulls to ground the idea. Lucas found those artifacts as fascinating as the Ark of the Covenant, and had intended to feature them for a Young Indiana Jones