Mudangchum(무당춤) means a traditional Korean shaman dance. Literally, it is danced by one or more Mudangs or traditional Korean shamans often in a trance state.
The title of this performance is Manshin(만신), the background music of which is blended with some modern instrument sounds. The dancers look as if they were really in a trance state!

Source: KBS1 국악 한마당 has all the rights.