Mantis Shrimp - "Their eyes (both mounted on mobile stalks and constantly moving about independently of each other) are similarly variably coloured and are considered to be the most complex eyes in the animal kingdom.
The Mantis Shrimp not only looks like a rainbow, it has the most complex sight in the animal kingdom. In other words, not only do they look like a rainbow, they can see far more colors in the rainbow than any other creature on the planet.
Sea life - Mantis Shrimp - A predatory marine crustacean with a pair of large spined front legs that resemble those of a mantis and are used for literally beating prey into submission. Ounce per ounce, nothing in the animal kingdom hits harder.
The Mantis Shrimp, feeds by smashing open its prey with a force that can break a pane of glass, and its darting bulbous eyes are thought to be the most complex in nature. Impressive for such a little guy!