A scorpion bit David Sullivan on the back of his right leg, just below the knee, then crawled up and down his left leg, he thinks, before getting him again in the shin. Not what he was expecting on his flight home from Chicago to Vermont. Sullivan, a 46-year-old builder, was aboard the United Airlines flight on the second leg of his trip home from San Francisco, where he and his wife, Helena, had been visiting their sons. He awoke from a nap shortly before landing and noticed something strange. "My right leg felt like it was asleep, but that was isolated to one spot, and it felt like it was being jabbed with a sharp piece of plastic or something." The second sting came after the plane had landed and the Sullivans were waiting for their bags at the luggage carousel. Sullivan rolled up his cuff to investigate, and the scorpion fell out. "It felt like a shock, a tingly thing. Someone screamed, 'It's a scorpion,"' Sullivan recalled. Another passenger stepped on the 2-inch (5-centimeter) arachnid, and someone suggested Sullivan seek medical help. He scooped up the scorpion and headed to a hospital. His wife stopped at the United counter and was told the plane they were on had flown from Houston to Chicago. The Sullivans surmised the scorpion boarded in Texas.