Sea turtles around the world face a serious threat from a fungal disease called fusariosis that destroys their eggs before they hatch. Scientists wanted to study how this fungus causes disease, but working with endangered sea turtles in tropical regions is difficult and heavily regulated. They discovered they could use eggs from red-eared slider turtles, an invasive species, as a substitute model to understand how the fungus infects eggs. The research showed that the fungus is highly virulent and modifies the acidity of egg surfaces to help it grow, providing valuable insights that could help protect endangered sea turtles.