In a world where prototaxites still existed, basically huge mushrooms, I think they would evolve into the small mushrooms today, just trees size. There would be a designated group that would live inside the mushrooms in the forest and would be called Mushroomians, and when you go into their house, they would have mush-rooms, and if the Mushroomians started a war against colonizers, it called the shroom-wars, creatin the slur "shroomies" and Mushroomians would probably get most along with moose and reindeer since they are the most animals to interact with mushrooms, and because of that it would be they would be domesticated making them like how we have cats and dogs. AND AND if they had instruments, they all be mush looking and have fun band names like mushtellica or The Rooms.