I wanted to create something with exaggerated subsurface scattering and rim lighting with a bright light source behind the mushrooms but I liked the contrast between the illuminated mushrooms and the dark blue I used for the sketch
so I made the mushrooms the Light source instead
I tried making the colors look smooth when the image is viewed at 100% scale but that, in turn, makes everything look a bit noisy viewed up close but that is a worthy pay off