The common octopus, the most widely researched octopus species, reaches up to approximately 39 inches in length and weighs as much as 25 pounds, according to Arkive. Other species are significantly different in size, ranging from about half an inch (octopus wolfi) to more than 14 feet (Pacific octopus).
Considered the most intelligent of all invertebrates, the common octopus is found in tropical and temperate ocean waters all over the globe. It has the ability to change its color and texture to blend into its surroundings in an effort to hide itself from both predators and prey. In the event that it is discovered, the common octopus releases a cloud of black ink to obscure the enemy's view and escape.