When the slime mold Dictyostelium discoideum runs out of food, sulfur limitation drives its development from a unicellular to a multicellular organism. Researchers now present the nutrient signaling pathways in this early eukaryote in great detail. Their results show how metabolism may have played a crucial role in the origins of multicellularity. Moreover, the findings also have therapeutic implications for more complex organisms such as humans. Targeting sulfur metabolism in cancer cells may enhance anti-tumor immunity.