In this mod called "VS Chara" you can battle the undertale character Chara with custom music, and charts.

Original Mod Link: https://gamebanana.com/mods/55836

Original Game Link: https://ninja-muffin24.itch.io/funkin

Ported by: xentidoe

Original Port Link: https://xentidoe.itch.io/vs-chara-full-week