A sex doll is a type of anthropomorphic sex toy in the size and shape of a sexual partner. The sex doll may consist of an entire body with face, or just a head, pelvis or other partial body, with the accessories for sexual stimulation. The parts are sometimes vibrating and may be removable or interchangeable. Sex dolls exist in many forms but are distinguished from sex robots, which are anthropomorphic creations designed to be able to engage in more complex interactions.