Ticks are blood-sucking parasites that can transmit diseases. The document discusses the blacklegged tick (Ixodes scapularis), which lives in wooded areas of the northeastern U.S. and can spread Lyme disease. It has a three-stage lifecycle as a larva, nymph, and adult, seeking hosts at each stage to blood feed and eventually reproduce. As carriers of Lyme disease, blacklegged ticks pose a health risk if not properly avoided or removed.