The book children of ruin explores the concept of a hyperintellegent cephalopods that build a planet and eventually discover faster than light travel. It's the second book in the series but great sci-fi book that explores different typee of consciousness.
If there is any animal that I could be convinced is not of this earth, it would be octopus. I’m disappointed that their DNA didn’t suggest this is a possibility ;-)
Even if it did, the authors wouldn't dare say it. "Scrambled" genome is pretty radical. If genetic transfer of material is commonplace we might expect aliens to be quite similar to us in terms of genes, but radically different in how those genes are composed... It's still an open possibility in my mind.
Cambridge University zoologist Arik Kershenbaum speculates on the form and function of alien life in his 2020 book, "The Zoologist's Guide to the Galaxy[1]." No time to read a book? Watch his Harvard science book talk[2].