 Grunge fused elements of hardcore punk and heavy metal into a single sound, and made heavy use of guitar distortion, fuzz and feedback.The lyrics were typically apathetic and angst-filled, and often concerned themes such as social alienation and entrapment, although it was also known for its dark humor and parodies of commercial rock.Bands such as Green River, Soundgarden, Melvins and Skin Yard pioneered the genre, with Mudhoney becoming the most successful by the end of the decade.