I love to work with color, but nothing I can come up with can match the amazing things that nature can produce. Take, for instance, the brilliant hues of Toxic Nudibrachs, photographed by David Doubilet for National Geographic Magazine.
The soft bodied sea slugs are pretty vulnerable except for the toxins they absorb from prey. Those toxins wind up creating amazing colors and patterns on the skins of the slugs, in addition to taking them off the menu of larger, faster predators.
Here's a related video