Writing Glenn Leopold Biography Screenwriter / Writer. Other Credits The Haunted Pumpkin of Sleepy Hollow Writer 2002 Scooby-Doo and the Alien Invaders Story 2000 Scooby-Doo! and the Witch's Ghost Writer 1999 Scooby-Doo on Zombie Island Story 1998 A Flintstones Christmas Carol Writer 1994 The Town Santa Forgot Teleplay 1993 The Twelve Days of Christmas Writer 1993 Monster in My Pocket: The Big Scream Writer 1992 The Adventures of Ronald McDonald: McTreasure Island Writer 1990 Scooby-Doo and the Ghoul School Writer 1988 The Smurfs: 'Tis the Season to Be Smurfy Writer 1987 Snorks: Bubbles of Fun Writer 1987 Back to Next Saturday Writer 1985 Too Scared to Scream Writer 1984 The Prowler Writer 1981 The Popeye Valentine Special: Sweethearts at Sea Additional Dialogue 1979 Agent-readable