What is Octopus Ink Made Of?

Octopus ink is one of nature's most theatrical defense mechanisms. But what is it made of?

The black ink is the combination of secretions from two glands. One creates mucus, which can affect the thickness of the ink...And the other is melanin, which gives the ink its black color. This melanin is the same color pigment found in dark hair, skin, and eyes. To scare and distract predators.