NEW YORK—Responding to retailers' calls to "streamline the Mark of the Beast," Satan announced plans Monday to make significant changes in the UPC symbol by the end of the millenium. "All men, small and great, rich and poor, slave and free, shall bear the mark of the beast," Satan said. The mark, "666," now hidden in every UPC symbol, may be more effective if taken off products and burned directly onto consumers' foreheads or hands, according to The Father of Lies. Said National Reserve Board Chairman Alan Greenspan: "As foretold in the Book of Revelations, it shall come to pass that no man shall be able to buy or sell without the Mark of the Beast." The new bar code system will be introduced through a series of televised public-service announcements featuring Friends star Matthew Perry and Satan, who will appear as a beast with seven heads and ten horns.