"Or take our situation, for instance, why do you say it isn't a manifestation of a supercivilization?"
"Hmm, too human. They've discovered that earthlings are on the threshold of the universe. Afraid of the competition, they decide to stop it. Is that it?"
"Because that's fiction. Dime-store fiction in bright, cheap covers. It's like trying to fit an octopus into a pair of tuxedo pants. And not a plain octopus at that, but an octopus that doesn't even exist."
— from Definitely Maybe, by Arkady and Boris Strugatsky.
Despite the awesomeness of the interwebs, there is an appalling dearth of images of octopuses in tuxedo pants, let alone any that approach what this passage conjures in my head. The occasional jacket-wearing octopus, yes. Also, people wearing tuxedoes while eating octopus. But no pants-wearing octopus.
There you have it. Proof that such an octopus doesn't even exist.
Note: It should not be construed that this novel is in any way about octopus — tuxedo pants-wearing octopus, space alien octopus, or octopus of any kind. There is some caviar, though. And to this point, there is some conjecture as to the existence of (non-octopus-like) space aliens. The quoted passage is a simple — and delightful — metaphor.