Octopuses are so weird, scientists are now openly wondering if they came to Earth from outer space.
Thirty-three scientists contributed to a new paper, published in an actual scientific journal, that proposes the eight-limbed molluscs arrived here as fertilised eggs aboard comets.
An alternative theory is that they evolved from squids after the introduction of alien DNA.
According to the scientists, the "remarkable evolution of intelligent complexity" that culminated in "the emergence of the octopus" around 270 million years ago defies what we know about Darwinian evolution - that it's a slow, gradual process.
They say the genes responsible for these rapid changes don't appear to have come from their ancestors.
"The transformative genes leading from the consensus ancestral nautilus to the common cuttlefish to squid to the common octopus are not easily to be found in any pre-existing life form," the study, published in Progress in Biophysics and Molecular Biology, claims.
"It is plausible then to suggest they seem to be borrowed from a far distant 'future' in terms of terrestrial evolution, or more realistically from the cosmos at large."
Yes, you read that right - they're saying it's more likely the octopus originated in outer space than travelled back in time from the future.
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Known as panspermia, the idea that Earth has been peppered with life from outer space gained popularity in the 1970s thanks to astrobiologist Chandra Wickramasinghe and astronomer Fred Hoyle.
At the time, we didn't even know if there were other planetary systems in our own galaxy - now that we know there are probably billions, the researchers say we no longer have to assume every single creature on Earth has a common ancestor.
"With astronomical data now pointing to the existence of hundreds of billions of habitable planets in our galaxy alone, such an hypothesis seeking an independent origin of life on any single planet seems to be no longer hardly necessary," the new study claims.
The researchers say there's evidence octopuses aren't the only creatures that may have hitched a ride here from out there. They propose the Cambrian explosion in evolution and life coincided with a more literal explosions - comets raining down on the planet, bringing new life with them.
They even suggest the asteroid that put the nail in the coffin of the dinosaurs was a life-giver, as well as taker.
"The exotic amino acids in the K-T boundary rocks and the rise of microfungi are also indicative of novel genetic material arriving in the impact."
Perhaps even we aren't as native to Earth as we thought.
"Living organisms such as space-resistant and space-hardy bacteria, viruses, more complex eukaryotic cells, fertilised ova and seeds have been continuously delivered ever since to Earth, so being one important driver of further terrestrial evolution, which has resulted in considerable genetic diversity and which has led to the emergence of mankind."
Fascinating, but other scientists have their doubts.
"Many of the claims in this paper are beyond speculative, and not even really looking at the literature," Portland State University biology professor Ken Stedman told Live Science, calling the paper "counterproductive".
He added that an extraterrestrial virus wouldn't even be able to infect a squid, unless it came from a planet which already had squid.
"I think that kind of assumption is highly unlikely."
Newshub.
