Michael Myers' killing spree has lasted decades, through multiple movies, continuities and timelines. Throughout the Halloween franchise, Michael has seemingly been killed multiple times, with multiple stabbings, gunshot wounds, fire, electrocution and other violent means. However, due to a clause in the original Halloween contracts, Michael Myers is not allowed to permanently die. Therefore, the filmmakers have found many creative ways to bring Michael back.
Source：https://www.cbr.com/halloween-h20-how-michael-myers-survived/
