Billy & Mandy in Trepanation of the Skull and You (1996 Billy & Mandy Short Film)

Maxwell Atoms created a student film in college with the characters Billy and Mandy that eventually became the main characters of the series "The Grim Adventures of Billy and Mandy", the two had different designs than they did in the show like Billy was taller and lankier and had a smaller nose and Mandy had pigtails, a nose (something she lacked in the series), and wore a black jumper with overalls.

The plot involved Billy wanting to release his inner demons so he decides to drill a hole in his head, Atoms described it as being completely innappropriate for Cartoon Network, he felt that the characters were too fun to use only once and decided that they needed another character to serve as the straightman of the group to balance them out and added the Grim Reaper to the cast.

In his interview with Pan Pizza of That Guy With The Glasses he mentions he has it in storage on film and said he will one day transfer it to digital media.