Depends on how you define colorful. If you mean “can see the greatest variety of color,” then the winner would have to be the peacock mantis shrimp. All of the colors a human eye can see come from just three kinds of color-receptive cells in the back of our eyes. The peacock mantis shrimp, in comparison, has sixteen kinds of color receptors, enabling it to see colors we can’t even imagine. If you mean “what animal displays the most color,” the answer again might be the peacock mantis shrimp, which shimmers with a rainbow of neon hues. But if you mean “colorful,” is in having interesting adventures—again, it’s the shrimp. Its fabulous fashion sense is only a cover for some ninja-worthy predatory skills. It attacks its prey with club-like appendages that it can move at the speed of a .22 caliber bullet, creating an underwater shockwave so powerful that it causes bubbles to emit tiny bursts of light. Brilliant.