Mettaton

Mettaton, or MTT for short (but still pronounced as "Mettaton"), is a ghost monster in a robot body built for him by Alphys. He is a famous, influential TV star that is very widely known, especially by Monsters. He currently is keeping up his brand and does many different TV shows of fairly diverse genres. He often visits the skelefam to hang out with Shae, as they're best friends.

Appearance
Standing at 7', Mettaton is a tall robot with short black hair with bangs that covers the right side of his face, metal segments on the left side of his face, white 'skin', black, sharp shoulderpads, and a magenta chestpiece. He has a curvy build and long arms. His torso contains his heart-shaped core.

He wears black leggings and magenta high-heel boots and makeup.

As a ghost, Mettaton is pink, transparent, and his bangs are still there, but is pink and transparent as well. He also has eyelashes.

Personality
As a TV host, Mettaton is confident, flashy, and charming. He loves violence, bloodshed, action, and bloodshed, especially if it's being recorded. However, Mettaton can sometimes ignore boundaries if he believes it is 'dumb'. Having a large ego, Mettaton wishes to always be in the center of attention and always boasts about his own beauty, being very narcissistic.

Despite all of this, Mettaton believes deeply in body positivity and will encourage anyone to explore cross-dressing and help them with negative body images one may have. He also does not wish to harm humans, even with the monsters' bad history with them.

Mettaton adorns his speech with tildes and calls everyone "darling". He likes to tell sex jokes, but it's typically to annoy people or used to ship others together (such as Wae and Tomiel).

Abilities
Mettaton has all standard monster abilities.

SOUL mode yellow: Though the SOUL mode is actually activated via the phone Alphys made, Mettaton can also change a target's SOUL mode to yellow.

Shae
During her time in the underground, Shae and Mettaton have become best friends. They often do each other's nails and makeup and go into town together.

Papyrus
Mettaton and Papyrus seem to be acquainted. Papyrus admires Mettaton and admits that he is sexy, and Mettaton in return thinks he's adorable. The two sometimes interract and seem to like each other's company.

Sans
Sans and Mettaton have a rivalry, due to their very clashing personalities. Despite this, Mettaton allowed Sans to do comedy routines in his underground resort, and Sans was willing to do routines there.

Trivia

 * According to Toby Fox, Mettaton is canonically (and ironically) straight.
 * However, Toby also states he's OK with any sexuality for him.