An Octopus has three hearts and nine brains.  The head has one central brain and eight brains are in arms.  Blood of octopus is blue colored.

THREE HEARTS

That makes sense, considering their bodies are all muscle except for two small plates anchoring their heads, together with a beak used to grasp and bite prey.  Two hearts pump blood to the gills.  A larger heart that circulates blood to the rest of the body.

BLUE BLOod 

The blood of the giant Pacific octopus has a copper-rich protein called hemocyanin that improves its ability to transport oxygen in cold ocean environments.

TOXIC INK

Octopuses have glands that produce a toxic ink which is then stored in large sacs.  When the animal is alarmed, it squirts the ink in a powerful jet in one direction that simultaneously propels the animal in the opposite direction, effectively clouding the water to confuse a potential threat while fleeing to safety.

THE ULTIMATE SACRIFICE

Giant Pacific octopus mothers sacrifice their lives after laying their eggs in deep-water dens.  They live with their eggs for up to seven months without eating, ensuring that streams of oxygen- and nutrient-rich water waft over them.  Mothers usually die after their broods hatch.