Giant Microbes Plush - BladderGiant Microbes Plush Bladder These Giant Microbes Dolls are a Million times their Actual Size! GIANT microbes are health and science products for humorous, educational, collectible, and Smart fun! Products include printed cards with fun fascinating facts. Unique gifts for students, scientists, teachers, health professionals & anyone with a healthy sense of humor! All About Bladder The bladder is a hollow muscular bag that lies in the pelvic cavity.