In this musical battle, you, together with the characters from Undertale, will have to fight the YouTuber Retrospecter in a musical battle. The game is done in neon colors and conveys the atmosphere of a humiliating battle. Reaction speed and agility will help you win. Controls are made with the arrow keys, which you have to press when they are shown on the screen. Hitting the beat will bring you closer to victory. If you make many mistakes, you lose and the game restarts from the beginning.