Randy Runyon, who entertained audiences in Southern California for more than a decade as Chucko, the clown character he took over from his father in the 1980s, died Wednesday at his home in Canyon Country. He was 57. His death followed a lengthy battle with lung cancer that spread to his liver, according to his wife, Joan. Runyon's father, Charles M. Runyon, created the character and starred in the Chucko the Birthday Clown show on KABC and KTTV in the 1950s and '60s. Children often waited years for the chance to appear on the popular show on their birthday with Chucko, who, with his finely painted clown face and spinning merry-go-round hat, became a Los Angeles celebrity along with such other kiddie-show stars as Engineer Bill, Sheriff John and Bozo the Clown.