What number in the series was last episode of South Park to use dialogue by a woman initially credited as Shannen Cassidy?
Starvin' Marvin in Space:  Like the episode Mr. Hankey's Christmas Classics, the episode is dedicated to Mary Kay Bergman, who lent her voice to nearly all of South Park's female characters. Mary Kay Bergman: Mary Kay Bergman (June 5, 1961 – November 11, 1999), initially credited on "South Park" as Shannen Cassidy, was an American voice actress and voice-over teacher.
i don't know