When single celled fungi began to work together, they must have evolved some means to pass food along from cell to cell, which enabled some cells to specialise in food intake, and others in micronutrients (for example).
Eventually something interesting happens: different parts of an organism appear, as individual genes are turned off in some parts and turned on in others.
We see, for the first time, structures of cells making up a single life form. Parts grow and specialise depending on what other parts are already present, and what is around them.
Many forms of multicellular fungi develop, some of which colonise the land at about the same time as the green plants.
Typically all this activity, for multicellular fungi, happens out of sight, as they consume dead matter from other sources, until eventually they have enough stored energy to reproduce. Only then do they grow the most specialised cells of all, the spores, hanging down from a fruiting body which we recognise as mushrooms and toadstools.
Over time, the energy and nutrient rich spores become a target for other, larger creatures, and defences are found in the form of toxic compounds. Some of these are mildy irritating, and will make a mammal sick. Some will kill. Some will affect the brain and cause visions.
Some become the basis of religions such as shamanism and the religions of the North American Indians and Alaskans.
You’ve come a long way: even humans worship you!
Oh… but there is one more thing. Something weird and interesting happens for some of you if you come in contact with green algae or cyanobacteria. Want to give it a try?