Apparently it is possible that winding up as calamari can be an octopus nightmare. Researchers believe they have filmed an octopus waking up from a bad dream.
An octopus nightmare may seem a stretch, but since some researchers think they may have arrived from outer space. So why not a nightmare?
The report comes from Smithsonian and details research done byThe Rockefeller University about a now-deceased reef octopus named Costello. The research in question has not yet been peer reviewed and is highly speculative.

Costello was rescued after a bad encounter with a predator, the magazine said. Curiosity was aroused one morning. A researcher noted his tank was inky. That tank, which he shared with small harmless fish, was monitored by a 24/7 camera. Costello appeared to awaken suddenly and display defensive behaviors including the inking. There is speculation he was flashing back to the attack.
Costello died of natural causes a few months into his life in the lab. A review of the footage showed three similar incidents.

Although octopi are now believed to be active sleepers, dream study appears nearly impossible. They seem to show active sleep patterns by changing colors at roughly 30 minuteintervals during a sleep session. It is thought to be something like human REM sleep. But rigging a spineless blob with electrodes to spot an octopus nightmare is beyond science today. It is also possible that the incidents were related to the disease that killed him. He may also have been suffering from senescence and lack or control of bodily functions. The researchers hope that other scientists will keep an eye on octopi and watch out for similar behavior.

Meanwhile there is speculation about where octopi came from. Some scientists argue for panspermia, the idea that octopi arrived on earth from outer space. That idea is borne of an accepted observation. Life on Earth appears to have burst forth suddenly and explosively. Some scientists think that life, or the most essential building blocks, arrived on as asteroid.
That asteroid crashed into the sea and took advantage of the hospitable environment of the ocean.
Proponents of the theory say that most of the earlier objections to the idea have been answered. It is now believed possible that life could survive on an asteroid and arrive alive on Earth.