The eyes of a scallop are made from guanine crystals, perfect smooth mirror like squares like what you’d find in a telescope. This highly reflective material is found in fish scales and chameleon skin. What’s exceptional about the scallop is that they have 200 of these blue telescopic eyes.
Scientists used computer simulations to find out how the mirrors in the scallop’s eyes work. They are also trying to understand how they combine the visuals from 200 different eyes into a single, cohesive image.
https://www.science.org/content/article/hubble-bubble-scallop-eyes-act-just-tiny-telescopes