Caribbean reef octopus (see this post)
The mimic octopus (Thaumoctopus mimicus), is a species of octopus that has a strong ability to mimic other creatures. It grows up to 60 cm (2 feet) in length. Its normal coloring consists of brown and white stripes or spots. It lives in the tropical seas of Southeast Asia on the bottom of muddy rivers and estuaries. The species was not discovered officially until 1998, off the coast of Sulawesi in Indonesia. For the next 2 years, scientists filmed nine different mimic octopuses impersonating sea snakes, lionfish, and flatfish—a strategy used to avoid predators. All octopus species are highly intelligent and change the color and texture of their skin for camouflage to avoid predators. Until the mimic octopus was discovered, however, the remarkable ability to impersonate another animal had never been observed.
fuckyeahaquaria: Blue Ring Octopus | Hapalochlaena maculosa (by Saspotato)
Blue ringed octopus (see this post)