The Code was alarmingly strict. It barred publishers from using the words 'crime,' 'horror' or 'terror' in their titles, thus forcing EC to abandon some of their most popular titles. Police officers could not be portrayed in a negative light, and if a villain committed murder, he would have to be caught and punished by the end of the story. No mention was allowed of vampires, werewolves or zombies, another swipe at EC. Years later when Marvel introduced zombies into their books, they had to call them 'zuvembies' in order to pass the Code. In general, DC and Marvel were supportive of the Code, but EC struggled to cope with the new rules, and eventually abandoned most of their titles to focus on "Mad Magazine", which did not need Code approval.