Okay, you probably did know that octopus sleep like most creatures, but apparently they also experience something humans do in their sleep.
As you may know humans, when in deep sleep state, are in full paralysis and cant move any limbs. In this state, the so called REM-Sleep, your eyes move randomly (REM=Random Eye Movement) and you are probably dreaming. Good thing arm and leg muscles cannot move, which keeps us from playing out what is happening in the dream ;)
And now we know this happens to octopus as well. Since Octopus are highly intelligent creatures and can learn from each other, and given they experience REM, does that mean they can dream too ?
I've read a novel from Steven Baxter ("Time") with squids replacing robots for space exploration, so its very fascinating to read about the actual science.
Read more on arstechnica.com: https://arstechnica.com/science/2023/07/octopuses-sleep-and-possibly-dream-just-like-humans/