Caddisfly larvae
Caddisfly larvae create a protective shell by taking whatever is nearby and attaching it around themselves, using their own silk to bind the materials together. Some artists have taken advantage of the unique way the larvae create their armor and the fact that they use anything around them to make it.
The artists left gold flakes, turquoise, rubies, and other gems for the larva to use, creating what is now known as entomological jewelry.