Black metal is an extreme subgenre of heavy metal music. It often uses fast tempos, shrieked vocals, highly distorted guitars played with tremolo picking, blast beat drumming, raw recording, and unconventional song structure. During the 1980s, a few thrash metal bands formed a prototype for black metal. This so-called "first wave" included bands such as Venom, Bathory, Hellhammer, Celtic Frost and Sarcófago.[1] A "second wave" arose in the early 1990s, spearheaded by Norwegian bands such as Mayhem, Burzum, Darkthrone, Immortal and Emperor. This scene developed the black metal style into a distinct genre.