Mold is an organism that grows where there is moisture by releasing spores. It presents a risk of allergy or toxicity to many people, and should be removed as soon as possible. Mold growth can be prevented by ensuring that anything that becomes damp is dried completely within 24 hours. Mold may grow in hidden places, such as in your carpet, walls, and ceiling. Removing mold can release a large amount of mold spores if not done properly, therefore the removal should be done by a properly equipped professional. Painting over mold is insufficient. If mold grows in your carpet, the carpet must be removed and replaced. You should let your apartment manager know about mold as soon as you detect it.
There's also plenty of mold doing what mold does in the great outdoors. As part of the town flora, it's an important part of the local biology. It also lends part of that distinct and earthy smell to the ground after a rain and under shade trees. Turning over mulch or even just poking into the soil, you'll find plenty of mold.
Tasty mold forms the basis of Quorn, available from many grocery stores.
Locations with known mold problems: - Cafe Casablanca