This article analyzes the development and reception processes for the pet-type robots known as AIBO in order to explore the multiple ways in which technoscientific practices make realities of the world. I investigate how practices of comparison work in the emergence of a new technological artifact. Specifically, this article focuses on a singular form of comparison, plastic comparison: comparison both shaping things and shaped by things. AIBO had been designed and understood by comparing the device with various existing entities: a technologically sophisticated machine, a pet animal, a computer game, and a family member. I analyze the way these comparisons gave this robot multiple shapes when it was developed in the laboratory, made it famous through media attention, and then created acceptance by its owners. I show that focusing on plastic comparisons is a useful way of exploring the multiplicity of technological practices that overcomes the limits of existing approaches in STS, such as the social construction of technology and actor-network theory.