The above illustration is from Life Among the Stars (1974) by V. A. Firsoff. It shows a tree octopus as representative of a hypothetical cephalopodesque lifeform that has the potential to evolve into a spacefaring species.
Firsoff imagines which types of lifeforms are most likely to follow an evolutionary pathway to sapience and eventually into space. Considering various Earth species as hypothetical candidates for proto-spacefarers, he notes that sealife is less constrained than landlife, which must deal with the vagaries of humidity and temperature on dry land, but:
these difficulties have honed the keen edge of perception and the thinking capacity of the land-livers to a general level above that of their marine counterparts, although some of the most intelligent animals are aquatic mammals, who have returned to the mother of all life after a prolonged evolutionary exile on the terra firma. The octopus, too, is a clever fellow.
He proposes that a lineage that begins with a clever octopus, already at an advantage over its marine brethren, venturing out of the sea and being honed by a challenging life in the trees is a very promising one:
[S]omething like an octopus, perhaps tree-climbing, is conceivable on land, especially in humid conditions; and, since this is a highly intelligent animal and equipped with limbs admirably suited for handling things, it could evolve to an industrial civilisation, which would be difficult for the dolphin, despite its large brain and developed language, because flippers are not much use for anything except swimming. Thus a race of pseudo-octopi may yet be piloting space ships!
This theme of certain species having more potential for sapience and spaceship-piloting was famously expanded upon by science fiction writer David Brin in his novels set in the Uplift Universe, where sapient patron species use genetic modification to nudge along other species deemed particularly ripe for sapience. Not surprisingly, Brin's Contacting Aliens describes one of these patrons, the Puber (the grand-patrons of the series' main antagonists, the Soro), as having been uplifted from a species that was "arboreal, a sort of tree-dwelling octopus". How could Brin not include something with such obvious potential?
So what of the Pacific Northwest Tree Octopus, our dear, endangered friend? Does it have the potential to follow the path that Firsoff charts to the stars? And if it does, how can we deny it its potential by refusing to do everything we can to save it from extinction? With the shame of our past crimes against it and the present indifference among many of us to its plight, perhaps we owe the tree octopus to not just save it, but to uplift it, so that one day Paxarbolis ab-Human can take its place in the Community of the Universe where it belongs.