Richard Steven Horvitz: Richard Steven Horvitz. Actor: Invader ZIM: Enter the Florpus. Richard Horvitz began acting professionally at the age of 10. As a child, he appeared in numerous stage productions. Among the most notable, the musical "Oliver!", starring Dick Shawn and Stubby Kaye. Also as a child, Richard starred in numerous commercials and made many television guest appearances on such shows as Diff'rent Strokes (1978), Head of the Class (1986), You Can't...