The Peacock Mantis Shrimp. Looks sure are deceiving here because this guy is what's known as a smasher, with club shaped raptorial appendages that it uses to repeatedly smash its prey until it can gain access to the soft tissue for consumption.
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.
Shrimp have never been known as powerful creatures, but the Peacock Mantis Shrimp is not an animal that you want to mess with. (And, for the record, the Peacock Mantis Shrimp is technically a crustacean.