Octopus and their relatives are swimming light shows, their surfaces covered by a million individually controlled color changing cells. A cuttlefish placed on a checkerboard can imitate the pattern, a fleeing octopus can make deceiving seaweed shapes coruscate backward along its body. Photophores of deep sea squid, some with irises and lenses, generate bright multicolored light. Since they also have good vision, there is a potential for rich communication. Octopus are reclusive and shy, squid are occasionally very aggressive.
Small octopus can learn to solve problems like how to open a container of food.
Giant squid, with large nervous systems, have hardly ever been observed except as corpses. They might be as clever as whales. Birds are vertebrates, related to us through a 300 million year old, probably not very bright, early reptile. Size-limited by the dynamics of flying, some are intellectually comparable to the highest mammals. The intuitive number sense of crows and ravens extends to seven, compared to three or four for us.