planets, with new worms and infinite potential for gathering spice. Prequels and sequels In the Prelude to Dune prequel trilogy by Brian Herbert and Kevin J. Anderson (1999–2004), the Tleilaxu initiate Project Amal, an early attempt to create synthetic melange to eliminate dependence upon Arrakis. They are fundamentally unaware, however, that melange production is part of the sandworm lifecycle, and the project is an abysmal failure. In Sandworms of Dune, Brian Herbert and Anderson's 2007 conclusion to the original series, the Spacing Guild is manipulated into replacing its Navigators with Ixian navigation devices and cutting off the Navigators' supply of melange. Sure to die should they be without the spice, a group of Navigators commissions Waff, an imperfectly awakened Tleilaxu ghola, to create "advanced" sandworms able to produce the melange they so desperately require. He accomplishes this by altering the DNA of the sandtrout stage and creating an aquatic form of the worms, which are then released into the oceans of Buzzell. Adapting to their new environment, these seaworms quickly flourish, eventually producing a highly concentrated form of spice, dubbed "ultraspice". Meanwhile, sandworms are revealed to have survived the devastation of Rakis after all, by burrowing deep under the surface. In adaptations Dune (1984) In the 1984 David Lynch film Dune, the sandworms were designed by special effects modeler Carlo Rambaldi for a budgeted $2 million. Rambaldi had previously created the titular alien for the 1982 film E.T. the Extra-Terrestrial. The blue screen constructed for Dune special effects was thirty-five feet (11 m) high and 108 feet (33 m) wide, the largest at that time. The sandworms were achieved using practical effect models, miniature sets and blue screens. Several scales of sandworm models were created, operated by "worm wranglers" and pulled with cables to simulate motion. The largest models, which were approximately 20 feet (7 m) long, allowed for wranglers to open the worms' mouths and crane their bodies up and down and from side to side. The smaller versions were used for other movements, and for background action. Critics were generally not impressed with the film's effects. Roger Ebert called Lynch's sandworms "striking", but noted, "the movie's special effects don't stand up to scrutiny. The heads of the sand worms begin to look more and more as if they came out of the same factory that produced Kermit the Frog (they have the same mouths)." Entertainment Weekly Sandra P.