Similarly, when an octopus changes skin color in self-defense, such as by mimicking a poisonous sea snake, the decision may come not from central command but from the skin itself.

WSJ: The Brains of the Animal Kingdom

It is here that you will find the depiction of the churning of the Ocean of Milk: Various deities taking part in what at first appears to be tug-of-war, but is in fact a search for a potion that will confer eternal life, a process that involves churning the sea with the help of an enormous snake.

BBC: Millennium mayhem at Angkor Wat