How squids and other cephalopods camouflage themselves:

A clue to how cephalopods disguise themselves so quickly came to Dr. Hanlon when he and his colleagues reviewed thousands of images of cuttlefish, trying to sort their patterns into categories. "It finally dawned on me there aren't dozens of camouflage patterns," he said. "I can squeeze them into three categories."

One category is a uniform color. Cephalopods take on this camouflage to match a smooth-textured background. The second category consists of mottled patterns that help them hide in busier environments. Dr. Hanlon calls the third category disruptive patterning. A cuttlefish creates large blocks of light and dark on its skin. This camouflage disrupts the body outlines.

It's not often you can find research on the intersection of security and squid.