The sleek, handset-like prototype was designed to integrate AI technology from SpaceX’s xAIElon Musk’s SpaceX SPCX -7.80% has developed a prototype for a handset-like device designed to reshape how humans interact with artificial intelligence that SpaceX has shown investors recently. The rocket and AI company showed the prototype, which features a sleek design that is slimmer than an iPhone, to some investors and other stakeholders ahead of the company’s mega initial public offering, according to people familiar with the matter. The prototype was designed to run on a proprietary operating system and integrate AI technology from SpaceX’s xAI, some of...