A nudibranch is a type of soft-bodied marine mollusk known for its vibrant colors and unique shapes. They belong to the class Gastropoda and are often referred to as "sea slugs." Nudibranchs can be found in oceans around the world, typically in shallow waters, and they feed primarily on sponges, anemones, and other small marine organisms. These creatures are notable for their lack of a protective shell, which distinguishes them from other mollusks. Nudibranchs have evolved various defense mechanisms, including the ability to absorb toxins from their prey, making them unpalatable to predators. Their striking appearance and fascinating behaviors make them popular subjects for underwater photography and marine research.