Tim Burton originally wrote the story in poem form while he was an animator at Disney. He really hated that job, by the way. “I couldn’t draw those four-legged Disney foxes. I just couldn’t do it,” he said. “I couldn’t even fake the Disney style. Mine looked like roadkills.”
Anyways, after his stint as an animator he kept in touch with another animator who didn’t quite fit the Disney mold, Henry Selick. Burton showed Selick his creepy poem about a skeleton-type dude named Jack Skellington, and Selick immediately wanted to direct a feature version. They recruited “Beetlejuice” co-writer Michael McDowell and set upon creating the film in 1991.