This video says about itself:
Prehistory of the Octopus
29 April 2018
Octopuses are an amazingly diverse lineage of creatures that have been evolving for hundreds of millions of years, and yet so little is known of their past.
By studying the genome of a kind of octopus not known for its friendliness toward its peers, then testing its behavioral reaction to a popular mood-altering drug called MDMA or “ecstasy,” scientists say they have found preliminary evidence of an evolutionary link between the social behaviors of the sea creature and humans, species separated by 500 million years on the evolutionary tree: here.
But the final days of a female octopus after it reproduces are quite grim, at least to human eyes. Octopuses are semelparous animals, which means they reproduce once and then they die. After a female octopus lays a clutch of eggs, she quits eating and wastes away; by the time the eggs hatch, she dies. In the later stages, some females in captivity even seem to intentionally speed along the death spiral, banging into the sides of the tank, tearing off pieces of skin or eating the tips of their own tentacles. (If you’re wondering, the males don’t get off any easier. Females often kill and eat their mates; if not, they die a few months later, too): here.