MacArthur "Mac" Foster (June 27, 1942 – July 19, 2010) was an American heavyweight professional boxer. Foster was known as one of the hardest punchers of his era, and it's said that he once knocked out the powerful and feared Sonny Liston during a sparring session. In his professional boxing career, he scored notable wins over top fighters such as Thad Spencer, Cleveland Williams and Zora Folley.