Scorpions light up a glowing green under ultraviolet light. Science isn't entirely sure how but has a few theories on why. (Y'know, aside from "Scorpions are metal.") Learn more about scorpions' fluorescence in this classic episode of BrainStuff, based on this article: https://animals.howstuffworks.com/arachnids/why-scorpions-glow-under-black-light.htm