Blue Effect was a Czech rock band, also operating under the names M. Efekt, Modrý efekt, or the Special Blue Effect, since their formation in 1968. The band's main and only permanent member, from its founding until his death in 2016, was guitarist Radim Hladík, formerly of The Matadors. Blue Effect changed their musical style several times, ranging from rhythm and blues, jazz fusion, to art rock.