Venezuelan security services are fighting the latest threat against President Hugo Chavez. Call it the pumpkin rebellion. Somebody left Halloween-style carved pumpkins outside the state petrochemical company, and outside the office of Chavez's political party. They carried messages encouraging protest. Bomb experts had to check out one of them. A few weeks ago, Chavez opponents hung paper skeletons around Caracas in what police called a plot to cause unrest.