Mayhem on the Disorient Express
Michael Gallager (writer), Warren Kremer (pencils and inks), Grace Kremer (letterer), G. Roussos (colors)
Published in Count Duckula #2, 01/1989.
DM makes a cameo appearance in the adventure that Count Duckula is having. In that single page he is shown talking to Ian Flamingo at a train station, agreeing to help Ian on his case. Then the 'editor' informs DM he is not due to show up until issue #3 so DM takes off in his car.