Megalopyge opercularis

The Megalopyge opercularis is a moth of the family Megalopygidae. It has a number of common names, like asp caterpillar, puss caterpillar, woolly slug and puss moth. 
This caterpillar is highly dangerous due to its venomous spines. Exposure to this caterpillar's fur-like spines leads to an immediate skin irritation. The pain is similar to bee, wasp or hornet stings. The reactions are often localized to the affected area. However, the reactions are usually severe. The reaction causes burning, nausea, headache, rashes, vomiting and blisters.
These caterpillars are seen from southeast Virginia to Florida and as far west as Missouri and Texas. They are also in Mexico and Central America.
If you are stung by a puss moth, asp caterpillar or puss caterpillar, get first aid right away. The spines need to be removed using cellophane tape. You can also use baking soda, ice packs or calamine lotion for the sting.