Mettaton originally appears as a gray, largely rectangular box with a 4x5 grid of rectangular lights at the top, similar to the mechanism in Snowdin Forest used for Papyrus's Tile Puzzle. The grid of lights can change colors between red, yellow, green, and blue, and Mettaton uses these color changes in place of facial expressions. He has four dials along the bottom of his body, and the bottom, he has a single leg which ends in a wheel. He has two segmented robotic arms which end in white gloves.