Golden tortoise beetle

Image from 9wows, via Pharyngula.

Also, according to Wikipedia:

They can change color, looking initially like tiny jewels, or golden ladybugs, but can alter the reflectivity of the cuticle so the outer layers become clear, revealing a ladybug type of red coloring with black spots. This color change is accomplished by microscopic valves controlling the moisture levels under the shell.

"A year at the shore"

Lovely illustrations of tidepool creatures from a book by 19th-century naturalist Philip Henry Gosse:

He also created some gorgeous illustrations of sea anemones.