Jack Skellington is the patron spirit of Halloween, portrayed as being on par with Santa Claus and the Easter Bunny within his own holiday.  He is the most important of many Halloween spirits, with the implication that their job is to scare people in the real world on Halloween night, though all in innocent fun. When Zero runs away, Jack becomes depressed and begins a campaign to find his lost friend. His vocal performance is to be reminiscent of Chris Sarandon (or Danny Elfman).