Mold is not a good thing for some people to smell or breathe. That fuzzy stuff growing on the food in your mold terrarium is mold, a kind of fungus. Unlike plants, molds don't grow from seeds. They grow from tiny spores that float around in the air. When some of these spores fall onto a piece of damp food, they grow into mold.
Green plants are green because they contain a chemical compound called chlorophyll.
Unlike green plants, mold and other fungi have no chlorophyll and can't make their own food. The mold that grows in your mold terrarium feeds on the bread, cheese, and other foods. The mold feeds itself by producing chemicals that make the food break down and start to rot. As the bread rots, the mold grows. It can be annoying to find moldy food in your refrigerator.