Do Octopuses Experience Nightmares?

Scientists have observed a male octopus undergoing sudden changes in body pattern and coloration when it was apparently asleep, suggesting that it was dreaming. The researchers believe that the octopus might also experience nightmares, as it was seen abruptly awakening before flailing its limbs and squirting out a bloom of ink, as if it was evading an attack. The study is based on observations of a single octopus, so it is not clear if this is universal behavior among the species. However, the mounting evidence of octopuses' intelligence and extraordinary brains suggests that they might have vivid dreams, reflecting the darker side of their existence.