Mettaton is the talented and charismatic crystal golem who runs his own carnival called MTT Carnival! Before he became the charming ringmaster of MTT Carnival, Mettaton was a hopeful ghost with the confidence to take any step to become a famous entertainer. One day, the royal alchemist Alphys was looking for a subject in an experiment that would put the subject's soul into a powerful crystal golem, and in the end, Mettaton accepted this opportunity to become something more. After this, he got everything that he wanted, the fame of being the best entertainer in the mountains!

He will based on Rhapsody Of Fire. Here is his themes: https://youtu.be/AzzzPHiUi9Q and https://youtu.be/MsHKQMJsKOs