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 episode of BrainStuff.Learn more about advertising on the HowStuffWorks podcasts at www.howstuffworks.com/advertisers.htmAnd to learn about your ad choices when listening to podcasts, visit https://www.howstuffworks.com/privacy.htm#ad-choices