A tad on the dramatic side, but still a good read: UT story on Scott Cassell and the Humboldt squid.
“After hearing the red demon legend, Cassell researched Humboldt squid for two years before he began diving with them. Humboldts, named for a current in the eastern Pacific, have a sharp beak, eight muscular arms and two retractable feeding tentacles that they use to attack their prey with more than 40,000 needle-sharp teeth at once….
“..Cassell made his first dive with a group of Humboldts that were feeding off Baja California. The squid, which often grow to be 6 feet or longer, immediately attacked, Cassell said, pulling his right shoulder out of its socket, yanking him down so fast his right eardrum ruptured and cutting him so badly his wet suit was destroyed…”
“…they have three hearts, blue blood that is copper-based, the ability to swim at about 24 mph and excellent problem-solving skills. They live in water as deep as 3,000 feet, are as smart as dogs and are able to communicate with one another by changing their skin color from white to various shades of red”
Update: Outside magazine did a great article back in 2006 on the Humboldt squid and Cassell: Behold the Humboldt