Meloetta is a Pokémon that has a femininely anthropomorphic figure with musical bar-style streaks in its hair, quarter notes (crotchets) (♩) for its arms and hands and pupil-less eyes resembling whole notes (semibreves). It has a jewel on its forehead and a black headpiece that seems to be shaped like a treble clef, which doubles as an attached microphone such as one often used by singers. Its ovular head seems to be a third of its body's height and about half its height in width. In its Aria Forme, Meloetta has light blue eyes and flowing, wavy hair with light-blue ovals that resemble whole notes. In its Pirouette Forme, it has auburn hair that seems to be stylized in a high bun and red eyes. In both forms, its midriff and eyes match its hair. It is a gender-unknown species.

According to artists in Unova, Meloetta's beautiful music and dance inspired many works of art, music, and songs. This made the Pokémon popular among both musicians and dancers. Meloetta's melody has a special vocalization method. Meloetta's melody can control the feelings of those who hear it. It can make both humans and Pokémon feel happy or sad through this method. The song can also unseal ancient ruins such as the Abyssal Ruins At one point, Meloetta can lose its signature melody and ability to dance should the world be filled with sorrow. Meloetta is capable of flying. Like many other Legendary and Mythical Pokémon, Meloetta is capable of temporarily turning invisible. Meloetta's song can be channeled to summon and control the original three Forces of Nature Pokémon in connection with the Reveal Glass. However, this process can cause Meloetta agonizing pain in the process.

Forms

Meloetta has two forms: Aria Forme and Pirouette Forme. Meloetta is the only known Pokémon capable of learning the move Relic Song, which allows it to change forms. In its Aria Forme, Meloetta can sing beautiful songs, while in its Pirouette Forme, Meloetta can perform graceful dances.

(source: Bulbapedia)