Actually mushrooms are fungi rather than plants. Fungi are distinct from both plants and animals (a separate "kingdom" of life), though genetic evidence suggests that they are actually more closely related to animals than plants - in the sense that their last common ancestor with animals was more recent than their last common ancestor with plants (though both were hundreds of millions of years ago). Sorry to be pedantic, but it sort of goes with my job.
The really fun thing about mushrooms is that they aren't the whole fungus, or even the larger part of it. They are just "fruiting bodies", a bit like flowers on a plant. The rest of the fungus grows through the soil as threads or moulds, usually unseen, and can be huge:
the largest organism in the world is a fungus from the group commonly known as "honey mushrooms". The "mushroom" itself is just something the fungus sprouts at certain times of year to disperse its spores.
As for how you hunt them, think of "hunting for a lost sock" rather than "hunting an antelope".
