Giant Microbes Plush - Booger (Mucus)Giant Microbes Plush Booger (Mucus) Dried nasal mucus is what we call boogers. Mucus is vital to your immune system since it catches wayward microbes before they reach your lungs. Surveys show that most people admit to picking their nose! Picking is not the best habit though, so why not pick this adorable little guy instead! All About Booger (Mucus) FACTS: Dried nasal mucus is what we call boogers. Mucus is a slimy goo vital to your immune system. In