This speculative design workshop explores the use of generative AI tools for musical instrument concept design. Workshop participants will use text-to-image AI tools to rapidly generate an abundance of instrument designs before refining designs into mock-ups to imagine how the instruments might be played and how they might sound. The designs produced in the workshop will be shared in a show and tell at the end of the workshop as well as a website and physical zine thereafter. The workshop to be interactive, social and hands-on. No prior experience of AI, design or musical instruments is required, all are welcome!