Each of the octopus's arms has a small cluster of nerve cells that controls movement, so the creature technically has eight independent mini-brains along with a larger central brain. Researchers have known about the octopus's unique biology for some time now.

Can octopus tentacles think?

Thanks to research done at the University of Washington in Seattle it appears that octopus arms are capable of extra-quick thinking. They can respond on the fly to things that they feel, without having to check with the brain first. The researchers describe how most vertebrates function as brain-down.

Does an octopus tentacle have its own brain?

An octopus' central brain – located between its eyes – doesn't control its every move. Instead, two thirds of the animal's neurons are in its arms. ... “The arm is a brain of its own.” This enables octopus arms to operate somewhat independently from the animal's central brain.