Interesting but impossible to prove as there is not any histological research done and could be easily an artifact, or a fake. As the skin looks healthy around

Interesting but impossible to prove as there is not any histological research done and could be easily an artifact, or a fake. As the skin looks healthy around the area without almost no color or texture response ...and the mushroom is displaced from a normal up-down position, ...and the frog is alive and didn't tried to remove it... ...and that we know that this genus of fungus is saprophytic and live on dead plants. Frog skin evolved to have a complex cocktail of chemicals, totally different than dead wood cellulose so, what is this mushroom eating exactly?. my bet would be that the Mycena is growing on a wood splint in the frog body. This is the safer explanation at this moment with this data. Mycena grow often on indoor pots at the extreme of sticks when the compost is cheap. Plant owners always are alarmed and ask about it. I'm not against changing the paradigm but would require much more solid data than this.