The two creatures known as John Halloween and Bill Congo were one of the many first successful attempts from the Horrorsmith. He created them in 1964. Whatever process he used granted them long lives. Halloween and Congo also became the first sentients to lose interest in the Horrorsmith's grand design. They went out on their own.
Most of what they do is low rent muscle for the Mob but when the cash flow is low for them, Halloween and Congo rob banks. They are wanted in connection to at least 18 known robberies in America.