* CaliforniaDoubling: Friendship, Maine, [[Film/{{Casper}} the setting of the film]], is a real place, but none of the movie was shot there. The downtown scenes were filmed in the more touristy Rockport, Maine, while most of the movie, including all the scenes involving Whipstaff, were filmed in California.
* CutSong: There was a musical number by the Trio called ''Lucky Enough to Be a Ghost'', which was cut because the special effects needed to create it would've blown the movie's budget right out of the water. It can still be found on the DVD in two versions; the first which includes plastic models of the Trio that would've been used as a guide for the animators, and then a second version of Dr. Harvey on his own which would've been used in the film had they not cut it.
* DawsonCasting: Mostly averted; all of the teenagers are played by actors between the ages of 13 and 15; Casper's voice actor is 14. The trope is only played straight near the end of the movie, with [[spoiler:a 17-year-old actor portraying Casper, a 12-year-old, during his temporary restoration to life.]]
* DeletedRole: A scene was filmed with Zelda Rubinstein shooting out of a chimney and shouting "Go toward the light!", reprising her role from ''Film/Poltergeist1982'', but it was cut.
* DeletedScene: In the mirror morph scene, Dr. Harvey was originally also going to get changed into Creator/StevenSpielberg. The cameo was actually filmed, but cut from the film for pacing reasons. Spielberg was actually very happy about this, feeling that he's not much of an actor and was quite nervous in front of the camera.
* DisownedAdaptation: Russell Harvey, heir to the Harvey Comics legacy, thoroughly hated this film and how it forced child-unfriendly humor and an overly-dark, completely pointless backstory into something so beloved for its innocence. He also expressed disappointment in Creator/StevenSpielberg, whom he felt [[TheyWastedAPerfectlyGoodPlot wasted the perfect opportunity]] for a legitimately heartfelt adaptation.
* CutSong: "Lucky Enough to Be a Ghost".
* MoneyDearBoy: The only explanation for the celebrity cameos. Or the long-term presence of Creator/EricIdle.
** Creator/ClintEastwood and Creator/MelGibson's cameos were technically done out of a favor to Creator/StevenSpielberg, though this probably played a part in it too.
* OldShame: Creator/ChristinaRicci in a recent interview does not look back fondly on this movie.
* OrphanedReference: There was originally a CutSong called "Lucky Enough to Be a Ghost", which would have ended with the Ghostly Trio hoisting Dr. Harvey up to the ceiling just as Kat walks in to ask him about having the Halloween party at Whipstaff. This explains Kat's line in the finished film about her father having "hit the ceiling" when he found out about the party. Creator/ChristinaRicci does deliver the line in a dry enough way to make it non-obvious that this it's supposed to be a pun, but it's still hard to imagine the mild-mannered Dr. Harvey hitting the ceiling in a figurative sense either.
* TheOtherDarrin: When Casper does an [[TheAhnold Ahnold]] impression, he's voiced by Creator/JessHarnell.
* StillbornFranchise: A sequel was in the works, though Amblin eventually shelved it, feeling that audience interest wasn't high enough for a follow-up.
* WhatCouldHaveBeen:
** A ride based on the film was in the works for the Ride/UniversalStudios parks, but scrapped as the movie didn't do as well as Universal was hoping.
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