Mettaton is a robot with a SOUL and was built by Alphys. Initially poised as an entertainment robot turned human killing robot, Mettaton is later revealed to have only acted as such so that Alphys could rescue the protagonist, feel important and become closer to them. Mettaton is the sole television star of the Underground.

Mettaton's voice is very flamboyant, and slow. He likes to stretch out the length of words just so that everyone can here, so make sure to give it your best, darling!