The sea creature known for its ability to change colors is the octopus. Specifically, species like the common octopus possess specialized skin cells called chromatophores, which allow them to alter their skin color and texture rapidly. This ability serves various functions, including camouflage, communication, and temperature regulation. By expanding or contracting these cells, octopuses can blend seamlessly with their surroundings to evade predators or surprise their prey. Additionally, changing colors can signal their mood or intentions to other octopuses, making them adept at both self-defense and social interactions within their species.