Scientists studied a medicinal fungus called Cordyceps militaris and discovered that a protein called CmOzf acts as a master controller of several important processes. When light shines on the fungus, it activates CmOzf, which helps the fungus produce spores for reproduction through a specific genetic pathway. Interestingly, when CmOzf is blocked, the fungus produces fewer spores but makes more pigments and beneficial compounds. This discovery could help improve the production of medicinal compounds from this fungus and its use as a natural pest control agent.