Paul and Jessica survive the attack and escape into the deep desert, where they are given sanctuary by a sietch of Fremen. Paul assumes the Fremen name Muad'Dib and emerges as the leader for whom the Fremen have been waiting. He teaches them to build and use Weirding Modules—sonic weapons developed by House Atreides—and targets spice mining. Over the next two years, spice production is nearly halted. The Spacing Guild informs the Emperor of the deteriorating situation on Arrakis and demands he rectify it.