A Merry Mirthworm Christmas is an animated television special, produced by Perennial Pictures. It premiered on the Showtime Cable Network in 1984. The film features a cast of Mirthworms which are described as cuddly little critters about two inches long, … Rachel Rutledge, Peggy Nicholson, G. Brian Reynolds, Russ Harris, Miki Mathioudakis Added on Peacock 2021-10-01.