Yup, for defense. The hairs are called urticating hairs and are barbed. They get embedded into your skin and make you itch like crazy. Some people are highly sensitive to them and they break out in a bad rash looking thing. Luckily i am not that sensitive to them although they do make me itchy. I just make sure they don't get in my eyes and that I don't breath them in. The versicolor at the top shoots poo as a defense which is kinda funny and gross at the same time.