Phellellipsillo is a benevolent power who taught the first myconids the secrets of potion-making through direct revelation. He is often depicted as a type of fungal world-tree, his mycelia reaching down through the planes. His only concerns are the protection of the myconid race and the pursuit of perfection through meditation. Like his people, his preference is always pacifism whenever possible.
Phellellipsillo's ultimate fear is that it will be consumed by the being known as Jilin. As a result, the great fungus has made peaceful contact with surface creatures who present themselves as enemies of the Vashar.
Phellellipsillo's existence is so prevelent to myconid society that they do not use names of symbols when reffering to it. Surface races occasionally use a white mushroom on a black plane to represent both the creature and the city.