A video of an octopus changing colors while it sleeps is raising a lot of questions about the mysterious sea creatures.
The footage aired in the new PBS documentary titled "Octopus: Making Contact."
In it, a marine biologist suggests the animal's color may correspond with its dreams.
Octopuses often change their skin color to evade predators or to conceal themselves when hunting.
However, the biologist says a color change this rapid is something he's never seen before.