It’s the octopus’s intelligence that causes such usual theses to float in the science literature:
A 2018 science paper that suggests that they might be is receiving new attention. The basic thesis is that the Cambrian Explosion, which produced most of the basic animal life forms we see today, was the outcome of extraterrestrial viruses carried on a meteor that crashed onto Earth 540 million years ago. The underlying theory is panspermia, a hypothesis espoused by Francis Crick, that some viruses and bacteria travel on the tails of comets or meteors and may take root on planets:
These comets could have introduced Earth to novel life-forms that evolved on other planets, including viruses, durable microorganisms like unearthly tardigrades or, as the new study suggests, even fertilized animal eggs from other worlds.Brandon Spektor, “No, Octopuses Don’t Come From Outer Space” at Live Science (May 17, 2018)
Tardigrades (water bears) do survivfe space conditions so an extraterrestrial origin cannot be ruled out in principle. But octopuses? Bear with us.
Now, a group of 33 scientists from respected institutions around the world have suggested these bizarre creatures descend from organic alien material. Their research, published in the journal Progress in Biophysics and Molecular Biology, ties the “remarkable” rise of octopuses and their cephalopod cousins to the theory of panspermia.Katherine Highnett, “Are Octopuses From Outer Space? Study Suggests Cephalopod Eggs Traveled to Earth on a Comet” at Newsweek (May 17, 2018)
The underlying issue is that octopuses are very strange and very smart (more on that in a moment):News, “Science paper: Could octopuses be aliens from outer space?” at Mind Matters News
Takehome: There is no simple way of accounting for how smart the eight-armed invertebrate is. So, even if we dismiss an extraterrestrial origin, we still face a mystery.
You may also wish to read: Octopuses get emotional about pain, research suggests. The smartest of invertebrates, the octopus, once again prompts us to rethink what we believe to be the origin of intelligence. The brainy cephalopods behaved about the same as lab rats under similar conditions, raising both neuroscience and ethical issues.