Critical Mass is the name of multiple musical groups across different genres and countries. 1) Critical Mass (Poland) – A death metal band formed in 2004 in Poland. 2) Critical Mass (Netherlands) – A rave and happy hardcore group formed in 1994 in the Netherlands. The group was created by producers Ed Bout and Dave Hasselaar, initially as a live act for ID&T Records. Later, singer Ludmilla Odijk and rapper Danny Haenraets, known as MC Energy, joined the lineup. Read more on Last.fm