Ghostly Trio

Since the 1995 Casper feature film, the Ghostly Trio's names have mostly remained Stretch, Fatso and Stinkie. In most appearances, they enjoy scaring people (in contrast with Casper). The group generally treats Casper as its own personal slave and mistreats him. Despite this though, the Trio does truly care about Casper and like him more than they're willing to admit and, on rare occasions, they even protect him, sometimes out of self-interest. Notably in the 2006 TV-film, Casper's Scare School, the Ghostly Trio is depicted as uncharacteristically nice towards Casper and the brothers display concern for him. For example, when Casper leaves for Scare School, the Trio cry.

Most of the time, the Ghostly Trio expresses a general feeling of superiority towards the living, sometimes degenerating into hatred, and, in the films from 1995 onwards, sometimes refers to humans as either "fleshies" or "bonebags". The 1995 film and spin-off cartoon series, however, show their friendship with Dr. James Harvey (Bill Pullman). At first, they demand he vacate their home and make his quest to learn about the afterlife difficult. They grow to like him and, certain that his obsession with finding his wife will make him become a ghost, consider expanding their group into a Ghostly Quartet. Of course, that would require killing him, but they ultimately prove unable to do it themselves (Harvey later dies in a manhole accident, but this proves temporary). After he stops trying to get them to cross over, they also keep their promise to briefly reuniting him with the spirit of his wife. The spin-off cartoon depicted them in a similar light, where they often harass the doctor, although out of mischief rather than hatred.

Stretch is the lanky leader of the Trio with a thick Boston accent. Stretch is the most aggressive at scaring the living by morphing his body, but he is said to be highly experienced at possession. Although he acts the harshest, he is soon revealed to have a soft spot, and is perhaps the most sensible in making important decisions. In a deleted song he claims to be schizoid-paranoid, and despite his intelligence, he can be very childish at times.

Fatso is obese and assumed to be the least intelligent, even though he is adept at singing and has a surprisingly strong knowledge of pop culture. He also has a huge appetite for food, regardless of the fact that it literally drifts through his body, constantly overeating and seems to be the most emotional. He treats Casper the same as Stretch and Stinkie, but can easily be manipulated. When Stretch and Stinkie ask about something relevant to a story, a running gag has Fatso asking about something unrelated.

Stinkie is the "middle child" and dubbed the "Larry Fine" of the group. Stinkie's special talent involves supernatural halitosis and body odor, which he prefers as his means of frightening "fleshies" who cross his path (sometimes announcing this by saying "Smell-o-gram!"). He has a penchant for puns and comedy and comes off as the sarcastic jokester, which Stretch tires of more often than not. Casper's Haunted Christmas shows his interest in modern technology. In the 1995 film, he is portrayed as quieter and more timid than Stretch or Fatso, as reflected by his friendlier face on the film's poster.

Fatso's appearance, voice, and love for food makes him comparable to Slimer, an apparition from Ghostbusters. In 1987 Harvey Comics sued Columbia Pictures (the film's distributor) for $50 million, claiming that the iconic Ghostbusters logo was too reminiscent of Fatso. The court ruled in Columbia's favor,[4] due to Harvey's failure to renew the copyrights on early Casper stories and the "limited ways to draw a figure of a cartoon ghost".

Casper's exact relationship to the Ghostly Trio varies. In the early comic stories, the unfailingly polite Casper never addressed any of them as "Uncle", suggesting that they were instead his elder brothers or cousins.

Casper's Haunted Christmas hints at a relationship. The Ghostly Trio refer to Spooky (Casper's cousin) as their nephew. Whether or not that makes them blood relatives, remains unrevealed.

In the 1995 film and spin-off cartoon, they are said to be his uncles.

In the film Casper Meets Wendy, Casper tells Wendy that the Trio are his uncles, but the previous film Casper: A Spirited Beginning claims that Casper is not related to the Ghostly Trio, meeting them for the first time when he runs away from a ghost school run by the evil ghost Kibosh. Attempting to prove their superior ghost techniques, the Trio train Casper in his ghost abilities; when contacted by Kibosh and his assistant, Snivel, they lie to Kibosh about being his uncles so that he can remain in their care. Casper had saved the Trio from Kibosh's wrath after having impressed him when Casper ingested a bomb that saved the Trio's home from being destroyed. The Trio returned the favour by more or less adopting Casper so he would not have to go to scare school under Kibosh's orders, therefore remaining a family as Kibosh stated family stays together and haunts together.