For most of the past two centuries, the scientific study of fungi was little more than a small, inconspicuous subfield of plant biology. Today, that is rapidly changing, as mycologists and their objects of study (fungi) are increasingly attracting young scientists and occupying the public sphere in both medicinal and environmental contexts. At the root of mycology’s popular ascendance is Paul Stamets, a self-trained mycologist, author, entrepreneur, and frequent public spokesperson. This essay offers a rhetorical analysis of Stamets’s most influential public appearance—a 2008 TED talk entitled “6 ways mushrooms can save the world”. In particular, I draw on theoretical frameworks in rhetoric and studies of expertise and experience (SEE) to explain how an amateur scientist holding no credentials beyond a bachelor's degree developed an authoritative voice as a thought leader in his field.