“South Park” creators Matt Stone and Trey Parker think the same irreverent enthusiasm that made the animated show a success is behind its second-year ratings slip. After hyping a first season-ending cliffhanger, they replaced the show’s regular characters with a pair of flatulent stick figures, an anti-establishment move they thought fans would appreciate — but they didn’t. “There’s something about when an idea comes up that just shouldn’t be done, it’s more exciting to me,” Stone says in the June 21 issue of TIME Magazine. “That’s probably a character flaw of ours. Sometimes it pays off huge, and sometimes it backfires.” It backfired.