One evening, while walking through the forest in Albisrieden, a neighborhood in Zurich, the duo observed some green light through their camera. Sometimes the fungi’s bioluminescence is so weak it cannot be seen with the naked eye. “Nowadays we always have our mobile phones or a flashlight, but to see bioluminescence in the forest, it has to be pitch black,” says Rudolf.

The artists collected some samples of the glowing specimen thinking it was Mycena haematopus, a known bioluminescent species. Back in their well-lit studio, they realized it was another species, Mycena crocata, the saffron drop bonnet mushroom, known for its saffron-colored milk, which had not previously been described as bioluminescent.