Dasymutilla sackenii, commonly known as the Sacken's velvet ant, is a species of parasitic wasp found in North America. The females are wingless and covered in dense, velvety hair, giving them a fuzzy appearance. They are known for their painful sting, which is why they are often referred to as "cow killers." Despite their name, they are not actually ants but are a type of solitary wasp.