This animal has three hearts and blue blood

The octopus carries three hearts and blood that runs blue. Two branchial hearts pump blood to the gills to collect oxygen, while a larger systemic heart sends that oxygenated blood to the rest of the body. The blue colour comes from hemocyanin, a copper-based protein that carries oxygen more efficiently than our iron-based hemoglobin in cold, low-oxygen water. When an octopus swims, its systemic heart actually pauses, which is why it prefers to crawl. It is a living workaround for surviving the deep.