The Southern Flannel moth caterpillar—also called the puss caterpillar or the asp—has one of the most painful stings of any insect in North America. It may look like Elvis’s hair on a good day, but under those flowing brown locks are hidden rows of stinging spines. They sometimes drop out of trees and may land on a person's arm or neck. If that happens, it's going to be a long day. The sting gets worse and worse over several hours before finally fading away. Allergic people may need to go to the emergency room. This remarkable caterpillar occurs from Maryland south to Florida and west to Missouri and Texas. Occasionally found in New York and Pennsylvania.