Even though 变態 does mean "metamorpheous" or "transform", but in Chinese and Japanese, it is also used to describe someone has abnormal fetishes or a pervert.
变 （Traditional version 變) = to change; to become different; to transform; to vary; rebellion
態 = manner, bearing, attitude
This guy in the black leather jacket is wearing a t-shirt that says "testicle".
睾 = testicle
丸 = small round object; pellet, pill