As discussed in comments previously, one of the coolest thing about octopodes and cuttlefish is their ability to camouflage themselves and otherwise control the pigmentation of their skin. An article from today’s New York Times discusses the phenomenon. The creatures certainly have some neat tricks:
Dr. Hanlon has watched octopuses perform what he calls the Moving Rock Trick. They assume the shape of a rock and move in plain sight across the sea floor. But they move no faster than the ripples of light around them, so they never seem to move.
The article also describes forms of visual deception used against other cuttlefish. Apparently, there are situations where a male cuttlefish “disguises its skin to look female, he can sneak up to the guarded female and mate. The sneaky male’s disguise may be so good that the other male may try to guard him as part of his harem.” An impressive and cunning trick, for any species.