The use of natural biological composite materials offers a unique opportunity to improve our sustainability patterns of production and consumption because of their abundant availability in nearly every ecosystem, their low energy manufacturing requirements and eventually their natural biodegradation. This chapter presents the design of the Fungus-Like Adhesive Materials (FLAM), a family of cellulose-chitin biopolymers, and the development of its robotic 3D printing technology. The material’s bio-inspired design, sustainability consideration and its characteristics are documented aiming to stress the pitfalls of modern bioplastics and propose an alternative approach to sustainable materials. Furthermore, the 3D printing technology’s development highlights the unique challenges and considerations required for enabling the use of water-based biological materials. The process characteristics, including their differences when compared to synthetic polymers, challenges in controlling their shrinkage during curing as well as the opportunities to deploy contemporary process control methodology, such as machine learning to address their natural variability are shared. Several experiments are presented aiming to demonstrate the versatility of FLAM including demonstrators of a wide range of scales. Additionally, their remarkable ability to be synthesized from urban waste sources, namely paper and food waste, highlights their potential for closed-loop urban metabolic cycles. Finally, several potential future applications of FLAM are presented. Those aim toward use-cases where the technology is deployed in production where cellulosic materials are already used, for substituting existing processes and products involving synthetic polymers, contributing toward the problem of plastics, as well as for scenarios where a new material process may seed design innovation.