 Metalcore has screaming, growling, heavy guitar riffs, breakdowns, and double bass drumming.Heavy metal-hardcore punk hybrids arose in the mid-1980s and would also radicalize the innovations of hardcore as the two genres and their ideologies intertwined noticeably, resulting in two main genres one being metalcore.The term has been used to refer to bands that were not purely hardcore nor purely metal such as Earth Crisis, Integrity and Hogan's Heroes.