For the scene where Casper drags Kat out the window and then takes her to the lighthouse, Christina Ricci had a piece of fishing line tied to her wrist to give the appearance of been pulled by a ghost.
A live-action sequel was proposed, and a preliminary script was drafted, when production wrapped. Unfortunately, Christina Ricci and Bill Pullman were attached to other projects, and would not be available for more than a year. The producers decided to produce a cartoon series instead.
A musical scene, titled "Lucky Enough to Be A Ghost," was scripted and filmed. The three ghosts sang about their mental problems during a session with Dr. Harvey. It was dropped because of cost; the animation would have cost a few million dollars.