Prototype is a friendly and curious robot with a white plastic casing, from which parts of his metal insides are visible. He has six horns—four on his head and two on his lower face—and four-fingered claws, all of which are colored pink, yellow, blue, and purple. He can easily remove his faceplate and has a habit of chewing on things. Though he may not show it, Prototype is smarter than Guest might think. He is autistic-coded and often expresses his curiosity with an 'o' shaped mouth and an inquisitive tone.