Assuming it’s not just something that got stuck on the outside, then I would imagine that the frog is immunocompromised in some way, either due to mutation or e

Assuming it’s not just something that got stuck on the outside, then I would imagine that the frog is immunocompromised in some way, either due to mutation or environmental exposure to something. Split gill fungus (Schizophyllum commune), is an extremely common saprotrophic (eats dead wood) fungus that is normally completely harmless to humans. However in immunocompromised individuals, it can colonize their lungs and kill them.