It's a sunny day on the beach and you're taking in the fresh ocean air as you stroll barefooted through the sand. Suddenly, there's a sharp pain in your ankle. Looking down, you see a litte red crab pinching at your skin, glaring up at you with his eyes on two stalks. He waves his pincers back and forth at you angrily, seemingly taunting you. You must have crossed into his territory, and the brave little crab came to defend it.