Core77 introduces us to the mushroom knife, which is a tool designed for the needs of people who search for mushrooms.
The blade is curved for cutting through the stem. The brush allows the user to clear away debris that may obscure the mushroom. A scale printed on the side can be used to measure the mushroom. This particular model by toolmaker Garrett Wade also has a compass just in case you're too focused on searching for mushrooms and get lost.
The standard mushrooms that get put on pizza taste like chewing on dirty rubber.
Others like portobello and shiitake are ok, but I could usually do without them in a dish.