Grzegorz Welizarowicz (1972) – a composer, a musician. Starting 1994 he has cooperated with MORDY band. Starting 1999 he has been creating music to performances and dance theatre films, among others, for: Dada von Bzudlow, Occasional theatre, Good Girl Killer, Anna Steller and others. A member and the founder of Good Girl Killer group (2005). He took part in the following, selected theatre projects:
1."Alien Anonymous", Julia Mach Dance Company, co-composer, Vienna, February 2010.
2."Delia" Anna Steller/Good Girl Killer, co-composer, Gdańsk, August 2009.
3.”Action” Good Girl Killer Company, co-composer, actor, playwright, Gdańsk, June 2008. 
4."Eden," Dada von Bzdülöw theatre, co-composer, Gdańsk, March 2006.
5."The Square. Version 06," Occasional theatre, co-composer, musician, Sopot, December 2005.
6."Good Girl Killer" by Good Girl Killer company; actor, co-composer; Żak Club, Gdańsk, February 2005.
7."Las Dos Caras del Patroncito" - acto El Teatro Campesino; actor, Plama, Gdańsk, June 2002. 
8."La Luta Continua" Anna Steller, co-composer, December 2001.
9."Las Dos Caras del Patroncito", "La Quinta Temporada" actors El Teatro Campesino presented by UCSD students, directed by: professor Jorge Huerta; actor, San Diego, California, USA, March 2001.
10."Nietota" by Dada von Bzdülöw theatre; a musician /co-composer, Gdańsk, June 2000.
11."Apartament 001" (Suite 001) by Dada von Bzdülöw theatre; co-composer, Gdańsk, January 2000.
12. "Komedia w dawnym stylu albowiem nic się nie zdarza” (An old-style comedy as nothing ever happens), Dada von Bzdülöw theatre; musician/composer, Gdańsk, February 1999.Selected discography:
EGO "Swiatowid" Antena Krzyku Unc. 1997.
Mordy "Normalforma" Antenna Krzyku Unc., 2000.
Mordy "Zapiski ze Strychu” (Notes from the Attic), Mordy rec., 2002.
Mordy "Anthology" Tone Industria, 2004.
Ikenga Drummers "Lustereczko” (Little Mirror) One World, 2006 
Mordy "Wielkolud” (Giant) mordy rec., 2008