Octopus is the only species with super high intelligence (by human standards) known to us that does not engage in any social activities. Primates and dolphins and dogs and so many others like to form social bonds, but octopus is solitary animal. Even in mating rituals a social distance is kept and often the female will snack on her lover afterwards.
Imagine, your whole body is brain, you can taste the world and see through eyes and skin. Everything is a vivid muted underwater dream.
What internal life does an octopus lead?
I imagine them being true poets, connoisseurs of internal landscapes contemplating the beauty and the absurdity of life.
"Book of Disquiet" by Fernando Pessoa could have been written by an octopus, quietly observing marine life in a safe shelter of its den.