Emily and Grady Tucker
Portrayed By: Brendan Fletcher and Mairon Bennett (TV)
The protagonist and his older sister. They move with their parents to Fever Swamp, Florida, and encounter a new wolf dog and attacks occurring on their livestock.
- Affably Evil: In the book after becoming a werewolf, Grady retains his human intellect and the story ends with him joining his dog out in the swamp to only hunt local wildlife. The TV episode ends more ambigulously though, suggesting that like Will, he won't be in control of himself when he transforms.
- And Then John Was a Zombie: Grady is bit by Will and becomes a werewolf himself at the end of the story.
- Annoying Younger Sibling: Mostly averted; though he kind of gets on Emily's nerves he's not that annoying compared to most Goosebumps younger siblings.
- Bratty Teenage Daughter: Downplayed with Emily. While she is skeptical and Grady mentions her "crying for days" about moving away, she isn't as bad as other examples of this trope.
- Cool Big Sis: Rather unusually for this series, Grady and Emily get along OK most of the time.
- Deadpan Snarker: Emily is shown to behave like this at times when around Grady.
- Foolish Sibling, Responsible Sibling: Downplayed, but Grady is less responsible and more adventurous than Emily.
- Gentleman and a Scholar: Grady is pretty smart for his age but rarely brags about it.
- Men Like Dogs, Women Like Cats: Grady instantly takes a liking to their new dog. Emily, however, is less than pleased. She complains about him a lot and at one point wishes for a cat.
- Platonic Life-Partners: Grady becomes this with Cassie, another resident in town, at the end of the book. Understandable, considering her only other friend, Will, disappears shortly beforehand, and she has no one else to hang out with.
The Swamp Hermit
Portrayed By: Don Francks (TV)
An eccentric old man living out in the middle of the swamp.
- Adaptational Villainy: Downplayed. In the book, he's every bit as harmless as he's made out to be, chasing the kids through the swamp only to let Grady go as soon as he's alone, and reveal that it was just a joke. In the TV episode, he's still not a bad guy and is just out to avenge his family, but abducting Grady and holding him captive was rather unnecessarily cruel.
- Cloudcuckoolander: Even if he's really not that bad of a person, it is more than a little weird to consider chasing kids through the swamp fun.
- Cool Old Guy: Despite his scariness earlier, he actually turns out to be pretty nice, and returns Grady to his home safely.
- Creepy Good: Mainly in the adaptation, where his behavior is a lot creepier, particularly when he abducts Grady and keeps him in a net, then starts howling at the moon. But in the end, he actually saves Grady, sacrificing his own life to save him.
- Dark Is Not Evil: Lives out in a cottage in the swamp and is frequently seen carrying dead and mutilated animals, but he's a really nice guy.
- Death by Adaptation: He survives to the end in the book, but in the TV episode, he's killed offscreen by the werewolf..
- Madness Mantra: Repeatedly shouts "I'm the werewolf!" while chasing after Grady, Will, and Cassie. Downplayed, though, in that he's not as crazy as he acts.
- Misunderstood Loner with a Heart of Gold: Not only is he not the werewolf, he is actually trying to stop the werewolf because it killed his family.
- Red Herring: For all his being hyped up to be the werewolf, he's not.
Will Blake/Werewolf of Fever Swamp
Spoiler
A streetwise local boy from Fever Swamp, Florida, and the first in a long line of werewolves to appear in the franchise.
- Affably Evil: He's friendly as a human, and even tells Grady he doesn't want to hurt him in the episode.
- Ambiguously Brown: He has vaguely Hispanic features in the Goosebumps Graphix adaptation.
- Arbitrary Skepticism: He frequently scoffs at the notion of werewolves, even when his friends are suspecting the Swamp Hermit. This could imply either he's trying to keep his secret as much as possible, or he's deeply ashamed of what he is.
- Big Bad Friend: To Grady.
- The Bus Came Back: In the movie, though his real name isn't mentioned.
- Composite Character: In the TV episode it's him, not Cassie, who is obsessed with werewolves and accuses the Hermit.
- Death by Adaptation: In the original story, he's driven off by Grady's dog and escapes. In the TV episode, he's knocked into the swamp and drowns. In fairness, the book still treats him as being gone for good, with Grady becoming the new Werewolf of Fever Swamp.
- Dying as Yourself: Sadly subverted. In the TV episode, he reverts partially to human form long enough to warn Grady... and then changes back before Wolf kills him.
- False Friend: Grady gets along very well with him. Will kills his family's deer, frames his dog, and tries to kill Grady himself as a werewolf.
- Nice Guy: As a human, anyway.
- Our Werewolves Are Different: A kid wolf.
- Parental Abandonment: Earlier in the book, he mentions his Dad telling him the story of Fever Swamp. When Mr. Tucker pays his home a visit, it's completely empty.
- Riddle for the Ages: How did this guy become a werewolf, and how long has he been here? What happened to his parents? Did he even know what he was?
- Tragic Monster: We don't know just how much agency he has as a wolf, but he does seem to avoid attacking people in homes, and begs Grady to stay back after changing back in the episode.
- Walking Spoiler: It's pretty hard to talk about him without mentioning his surprise reveal.
- The Worf Effect: In his book appearance, he gets fought off by Grady's dog. And in The Movie, he gets owned by a nerd with a silver tooth filling. Definitely not cut out to be a werewolf.
Cassie O'Rourke
A local girl from Fever Swamp, Florida who has an obsession with werewolves.
- Adapted Out: She does not appear in the TV episode, though she is mentioned in the comics.
- Cloud Cuckoolander: She's a bit of a werewolf fanatic, much to the annoyance of Grady and Will. Even after the werewolf is defeated at the end of the book, she still looks out for werewolves.
- Redheads Are Uncool: Will and Grady think so, namely due to her werewolf obsession.
- Youthful Freckles: Is described having freckles in the book.
