Some of the specimens I cultivate show some very strange forms after lengthy growing periods. They develop into mushroom-like forms as seen on trees. These are very small though, and it shows that there is a whole complexity to the life stages of some fungi.
These can grow from components barely visible as seen under high power magnification under the microscope. In other words, the fungi is in the body as an undetectable form. Once it is released from the closed system of the body, it morphs---like a butterfly, into other forms more suitable for existence in it's new environment. So, if we are exposed to certain fungi in our environment or food, there may be some strains that can parasitize within a host. Shroom