Researchers identified how a deadly fungus called Aspergillus fumigatus uses a special nutrient (GlcNAc) to survive and cause disease. They found that a protein called RonA controls this nutrient processing and also helps the fungus hide from the immune system by building a protective outer coating. When RonA is disabled, the fungus becomes much less dangerous because the immune system can recognize it better. This discovery suggests RonA could be a new target for developing antifungal drugs.