The term "devil squid" is usually used in reference to the Humboldt squid, which has a reputation of being highly aggressive. They have attacked divers and been observed engaging in cannibalism.
They derive their name "devil squid" from the Spanish "diablo rojo," which means "red devil," because of their bioluminescent ability to flash red and white colors when hunting. With a mantle measuring up to 6 1/2 feet and a weight of 100 pounds, the Humboldt is one of the largest squid species in the world. Its eight tentacles are covered with 100 to 200 suckers, inside of which are teeth. Once the devil squid latches onto its prey, it pulls the prey toward its razor-sharp beak.