I would like to know the punishment in the grave (hereafter) for dancing to music.

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

Music is forbidden, this is discussed in Fatwa no 81545 and 81239.

The words of Allah and the saying of the Prophet (Sallallahu Alaihi wa Sallam) are a sufficient threat about listening to music and instruments of amusement. A listener to such things is threatened to be severely punished in the Hereafter.

However, we are not aware of any specific text or Hadith about the punishment in the grave of whoever dances while listening to music.

Allah knows best.