Mettaton is a robot. He persues Cameron throughout Waterfall.
Mettaton acts passionately about everything he does. He's quick on his ideas, and assumes all humans are evil. He wants to defeat the protagonist, but he also wants to be fair, and explain "Pink Mode" to Cameron. He likes to help with various activities. He hates puzzles and loves japes. Muffet watches anime with him, and says it's "Human History".
Mettaton has black hair that covers an eye and pink eyes. He has metal fragments on his face. During the Merciless battle and Muffet date, his hair is similar to Mettaton NEO's.
During the persuits, he wears silver armour with a helmet. He launches lightning bolts instead of spears. During the faux battle and hangout, he's wearing a pink T-shirt, jeans and pink boots. During the Merciless battle, he's wearing silver armour with a pink monster soul on the chest plate, pink gloves and pink boots. During the Muffet date, he's wearing his pink T-shirt, a denim jacket, jeans and boots.