For Luigi the lobster, it was simply time to grow. Literally. The spineless American lobster (Homarus americanus) recently molted—when a crustacean sheds its outer shell—in front of visitors to the New York Aquarium in Brooklyn. Luigi is an unusual shade of orange that is only seen in one in 30 million American lobsters. “On the morning in question, keeper staff discovered a molt in Luigi’s habita...