A’ight, so here’s the deal. My human version of Mettaton takes after my interpretation of Hapstablook, who is a leetle ghost with freckles, buck teeth, and wears a bowtie. In my take on the Overtale/Humantale AU, Happy was the flamboyant cousin of Nappy Blook, who went through a lot of heartache and internal (and sometimes external) suffering, and longed to start his life over with a new look and a new life. His friendship with Alphys led to the idea of him running away with her and helping her become the king’s Royal Scientist, and in return she would help him become the star he always dreamed of being. What he never mentioned to her was that he’d be abandoning his cousin, Nappy, whom he grew up with and loved dearly, but went through with it and decided to never discuss it ever again in the hopes of avoiding possible consequences for his actions.
Originally I thought of giving the Blook cousins the surname “Mettler”, so that Happy would have a closer way of coming up with his stage name, Mettaton. But I changed it so that Mettler was instead the maiden name of Happy’s late-mother.