Lauren Goode of the Verge writes about an encounter in Costa Rica with a crustacean called the Halloween Crab:
Only later, once I was able to connect to WiFi, did I learn that we had just had our first encounter with Gecarcinus quadratus de Saussure, otherwise known as the Halloween crab. And only later, in the light of day, did I see how awesome they are.
Halloween crabs are nicknamed so because of their brilliant colors — they have a tar-black carapace, blood-orange legs and purple claws, with a pair of yellow spots behind the eyes. They are land crabs in little technicolor dreamcoats. They measure around two inches across the carapace and four inches from claw to claw, but they have an adorable way of making themselves bigger when you near them, putting up their claws as if to say “It wasn’t me!” while they scuttle away.