How do Octopuses protect themselves from predators?

Octopuses like chameleons are able to change their colour and even their skin texture to blend into their surroundings so that their enemies cannot see them. Octopuses can further hide themselves by spraying ink at an attacker. This dark makes it difficult for an attacker to see the octopus giving it time to get away. Further the ink interferes with the attackers abilities to smell which can further throw of predators like sharks that rely on their sense of smell to hunt.