Harcore wrestling is a form of professional wrestling that eschews traditional concepts of match rules in favor of matches that take place in unusual environments, using foreign objects that are not normally permitted. Although hardcore wrestling is a staple among some wrestling promotions, where they are used at the climaxes of feuds, some promotions (such as Big Japan Pro Wrestling and Combat Zone Wrestling) specialized in hardcore wrestling, with many matches performed in this manner. Terry Funk and Mick Foley are often seen as the "Kings of Hardcore".