Of the approximately 100 species of cuttlefish, the giant is (unsurprisingly) the world's largest. This one, filmed near Whyalla, South Australia, is in the middle of a mating ritual, showing off its ability to display an entire color spectrum on its skin. As the crew was returning to the boat, one member yelled that he'd spotted the cuttlefish. So they grabbed fresh tanks and went back down for more than 5 hours.
The cuttlefish's colors can change based on whether it is experiencing aggression, fear, or sexual excitement; Hall even remembers seeing one go from ivory to bright red after eating a passing fish. Of course, nature isn't without a sense of humor: Despite all of these color changes, the giant cuttlefish is color-blind.