Holy Fodder. It’s well worth seeking out, as one good tuck-in ensures immortality for 500 years. It’s also prized by DAOists for clearing the mind and has many other miraculous properties.
Descriptions vary from a sort of grass to a mysterious mushroom, and it grows on three islands far from any beaten track. However trespassers may be stoned.
Of course you could try your local health food store. Just ask for Ganoderma Applanatum. It cures all known ills, relieves allergies, treats liver disease and leukemia, elevates the mind, cures depression, and tastes delicious in a sandwich.