This movie takes elements from Zombie Island, Witch’s Ghost, Alien Invaders as well as Cyber Chase by having supernatural elements in the story as real. The movie’s significant in showing Shaggy and Scooby as main characters, something not seen since the late 1980s. Though the film is a bit more light-hearted, it’s the fifth as well as the second to last What's New Scooby Doo?-based movie.
It's Halloween night, and the gang has decided to visit a Halloween carnival. However, when a magician, "The Amazing Krudsky", does not allow Scooby into his show, Shaggy and Scooby both decide to expose him as a fraud. After Shaggy and Scooby succeed in ruining his show, Krudsky returns to his dressing room, where a fairy, Princess Willow, inadvertently causes him to discover an entry on the Goblin Scepter in a spell book. She decides to toy with him, but he eventually discovers her, and drains her magic so he can become a real magician.
Shaggy and Scooby, after trick-or-treating all night, persuade the gang to let them hit one more house. When they arrive, they meet Mr. Gibbles, who tells them that the building is actually a genuine magic shop, and that magic exists. However, Princess Willow flies in at that moment, being chased down by Krudsky. He captures her, turns Gibbles into a rabbit and steals all the magical equipment before he leaves. Gibbles then explains to Shaggy and Scooby that the only way for Krudsky to be stopped is for them to enter the world of magic via Grim Reaper Railway and retrieve the Goblin Scepter before Krudsky does. But if they don't make it back before sunrise, then they'll be trapped in the magic world forever.
The film provides examples of the following Tropes:
- Actor Allusion:
- The Goblin King has some resemblance to the Lord of Darkness in Legend (1985), who Tim Curry also played.
- Hayden Panettiere voicing a tiny princess with wings nods back to her voicing Dot in A Bug's Life.
- Afterlife Express: The Grim Reaper Railway is a train full of skeletons.
- And Your Little Dog, Too!: After the duo ruin his act, Krudsky vows to get Shaggy for this and then threatens Scooby for good measure before closing the curtain.
- Armor-Piercing Question: Scooby and Shaggy are about to leave the magic shop outright, but Mr. Gibbles plays a horrible vision of what's to come if they do. It essentially leads off with this and gets their full attention.Daphne: Scooby-Doo, where are you?!
- Bait-and-Switch: Mr. Gibbles enters in shadow, speaking in a threatening tone and seeming to be trouble. He turns out to be a kindly old man and happily welcoming Shaggy and Scooby to his shop.
- Batty Lip Burbling: Velma does this to show that she's completely lost it after witnessing that magic is real.
- Big Eater: Shaggy and Scooby, as usual, have enormous appetites and eat constantly. Of course, they're trick-or-treating.
- The Cameo: There's a bunch of Scrappy Dolls, that get innocently run over by a monstrous hijacked mystery machine (hmmmm) and Krudsky flips through a picture depicting the title character of Fangface.
- Casting Gag: Fairy Princess Willow is voiced by Hayden Panettiere, who voiced Ant Princess Dot in A Bug's Life.
- Continuity Porn: When Shaggy and Scooby are in the tavern, you can spot many of the monsters they encountered in previous series.
- Covers Always Lie The Goblin King is actually the good guy instead of the Big Bad as people may believe when looking at the cover.
- Darker and Edgier: The film is a bit darker than standard Scooby-Doo fare, seeing that the main villain is an evil wizard who tries to lead monsters into taking over the world of mortals.
- Dark Is Not Evil: As it turns out, the Goblin King really isn't a bad guy. In fact, he's Willow's father and was willing to sacrifice his powers to keep her safe.
- Demoted to Extra: Fred, Daphne and Velma. As is with the late-2000s direct-to-video Scooby-Doo movies, the three play a much smaller role than they usually do; the movie primarily focuses on Scooby-Doo and Shaggy.
- Disproportionate Retribution: Sure he acted a bit rude about it, but Shaggy and Scooby ruining Krudsky's magic show and career just because he didn't allow dogs in to watch his show went more than a little overboard when it came to payback. To be fair though, this does cause them and the rest of the gang to get kicked out of the carnival.
- Distressed Dude: After making it to the castle of the Goblin King and sneaking in, Shaggy and Scooby blow their disguises, and are immediately sent to a tower in chains.
- Dramatic Thunder: When Mr. Gibbles makes his entrance at his magic shop house, with some really LOUD and real-sounding thunder.
- The Dreaded: The Goblin King, to the point where the other monsters in the tavern flee in fear when Shaggy asks for directions to the king's castle.
- Entertainingly Wrong: Daphne and Freddy assume that the Goblin King wants to do something horrible to Fairy Princess Willow when they see Krudsky using her to bargain with the Goblin King. It turns out he's her father, and was worried about getting her back safely.
- Evil Laugh: Krudsky upon claiming Willow's magic.
- Faint in Shock: Velma faints when she sees the supernatural maelstrom the Great Krudsky had created.
- Flying Broomstick: The witches loan Scooby and Shaggy a flying broomstick to use as transportation in the Goblin Kingdom.
- Forced Transformation: Krudsky's major form of attack once he gains magical powers is to turn people into stuff against their will. He turns Gribbles into a rabbit, Velma into a werewolf, Fred into a vampire, Daphne into a witch and the Goblin King into a goose. Additionally, Shaggy and Scooby are turned into a snail and a mouse by the witches in the Dead Bogs.
- Foreshadowing: Remember the part when Daphne, Fred and Velma look through the cutout board of a witch, vampire and werewolf at the beginning of the movie? Yeah, guess what they temporarily turn into respectively later in the film.
- The Goblin King is notably shocked when he finds out that Krudsky has Fairy Princess Willow... and is awfully quick to agree to his terms after that, doing so with bitter resignation. Which makes sense - Krudsky has basically forced him into a Sadistic Choice by threatening his daughter's safety.
- The Greatest Story Never Told: As the Goblin King erases Fred, Velma and Daphne's memories of everything they saw on Halloween night, Shaggy and Scooby are the only ones in the human world to remember their adventure and they saved the day.
- Headless Horseman: Shaggy and Scooby are chased by a headless horseman once in the world of magic.
- The Hecate Sisters: The witches consist of an aged witch, a middle-aged witch, and a young witch.
- Heroic BSoD: Once Krudsky obtains real magic power, Velma's logical brain shuts down.
- Heroic Sacrifice: Jack O'Lantern. Don't worry, he gets better.
- Hostage for MacGuffin: The Goblin King agrees to give up his staff in exchange for Fairy Princess Willow. It makes more sense when we learn that she's his daughter.
- Hot Witch: The Cat Witch (as she is identified in the credits) is very attractive.
- I Have Your Wife: The Goblin King's daughter, Willow, who was kidnapped by an unknown enemy. The gang is more sympathetic toward the Goblin King when Willow calls him "Daddy".
- Idiot Ball: The crowd attending Krudsky's act boo Krudsky after Shaggy and Scooby sabotage his show, even though, as a stage magician, his "magic" is supposed to be parlor tricks. Apparently, there wasn't a single attendee who did not expect his "magic" to be real.
- Inherently Funny Words: "Out of the way. I must go blow-dry my cummerbund."
- Ink-Suit Actor: The young Cat Witch resembles Grey DeLisle, who voices her.
- Irony: Shaggy and Scooby are not afraid of Halloween, despite the fact that they get freaked out by guys in costumes every single day of the week, though they have good explanation for this. They know everyone is in costume and the point of the holiday is meant to be fun, so there's no reason to be scared (least by no one with malicious intent). Plus, y'know, free candy.
- It Only Works Once: The magic cards Mr. Gibbles gives Shaggy and Scooby can only be used once, and their effects only last a short time.
- I Want My Mommy!: Krudsky can be heard yelling "I want my mommy" when the Goblin King drags him away.
- Laser-Guided Amnesia: The Goblin King erases the events of the night from Fred, Daphne and Velma's minds. Shaggy and Scooby are allowed to keep their memories, though, as a reward for proving their courage.
- Laser-Guided Karma: Shaggy and Scooby (along with the rest of the gang) get kicked out of the carnival for wrecking Krudsky's act.
- Leg Focus: A feminine iron maiden
screams and lifts its bottom section like a skirt, showing a pair of attractive legs as it runs away. - Literal Metaphor: Shaggy and Scooby gain a magic potion made from scratch. Cue the scene shifting to one of the witches on a tombstone that reads "Here lies Scratch" and giving a wicked laugh.
- Magicians Are Wizards: Krudsky drains Princess Willow's magic to grant himself real magic powers.
- The Man in the Mirror Talks Back: Scooby realizes Mr. Gibbles's magic shop is the real deal when his reflection trolls him.
- Monster Mash: The film features witches, goblins, skeletons, werewolves, and other creatures of the night.
- Ms. Fanservice: Daphne in her catwoman costume.
- Mythology Gag:
- The movie itself is one big throwback to the "Superstars 10" movies where Scooby and Shaggy faced with real supernatural world inhabitants (Scooby-Doo Meets the Boo Brothers, Scooby-Doo and the Ghoul School, and Scooby-Doo! and the Reluctant Werewolf).
- Mr. Gibbles conjures the Black Knight Ghost during his song.
- Some of the real monsters resemble the fake ones from the original series, like the Creeper and the werewolf/Silas Long.
- His head covered in cotton candy, Scooby licks it all off. This echoes the ending to the original Scooby-Doo, Where Are You! intro (which was clipped from the episode "Foul Play In Funland").
- Scooby and Shaggy sneak into the Goblin party by dressing themselves up like Velma and Daphne respectively, the same Wholesome Crossdresser outfits they tried using to get into a costume party in Scooby Doo! Pirates Ahoy!.
- Never My Fault: Both Shaggy and Scooby don't want to take the blame that their sabotaging Krudsky's show led to his villainous plot. On the other hand, they are roped into stopping him.
- Our Werewolves Are Different: Shaggy and Scooby encounter a bouncer, who is a werewolf, and Velma also turns into one. The difference about this two is that this one has light blue fur has light blue fur without a tail while Velma has brown fur and a tail.
- Out of Focus: Fred, Daphne and Velma are in the story but play a bit role at best. This is all Shaggy and Scooby.
- Papa Wolf: The Goblin towards his daughter Willow. When Scooby and Shaggy save him and Willow, the King gives Krudsky exactly what he wants.
- Pumpkin Person: Jack O'Lantern, a sentient pumpkin, is worn as the head of the Headless Horseman. He's not exactly pleased with the ordeal.
- Reasonable Authority Figure: The Goblin King proves to be this. It turns out Willow is his daughter, and he was unwilling to let a random mortal endanger her. That's why he agreed to give up the staff for Willow's safety. The Scooby Gang accidentally messes with that plan, but Scooby and Shaggy make up for it by stopping Krudsky. As thanks, the Goblin King lets the two keep their memories of the night. He also tells Willow she's grounded but is relieved she's safe.
- Resigned to the Call: When Mr. Gibbles says it's up to them to save the day, Shaggy and Scooby try to opt out. Gibbles gets their cooperation by showing them a vision of what will happen to Fred, Daphne, and Velma if Krudsky isn't stopped. He adds that others will suffer similarly, as well.
- Sadistic Choice: Krudsky basically forces the Goblin King into this - ransoming his daughter's safety.
- Sanity Slippage: Velma goes temporarily insane when she sees a real live fairy.
- "Scooby-Doo" Hoax: Surprisingly averted. All the monsters are real this time, with none of them being disguised criminals as is usually done with the franchise.
- Screams Like a Little Girl: A vampire lets out a feminine scream in response to Shaggy asking where to find the Goblin King.
- Shout-Out: When Krudsky skips through the book he passes a picture of Fangface.
- Skeletal Musician: The band in the monster bar that Scooby and Shaggy stumble into while searching for the Goblin King's castle are skeletons.
- "Take That!" Kiss: Scooby gives a mocking kiss to the Goblin King just before taking his scepter.
- Took a Level in Badass: Shaggy is displeased over "the not-so-amazing Krudsky" getting a major power boost.
- Took a Level in Jerkass: Scooby and Shaggy ruin Krudsky's act and don't even apologize. Granted, Krudsky brought it all on himself by rudely denying Scooby admittance, but still.
- Trauma Button: Shaggy and Scooby humiliating Krudsky by revealing all the ways he does his act. It turns out Krudsky has spent a lifetime failing to find real magic, which makes what Shaggy and Scooby did even more personal than they would've thought.
- Undead Barefooter: Three barefoot girls come out of coffins during the Bump in the Night song.
- Vine Swing: Scooby does this to save Shaggy from the Headless Horseman when he is being chased through the swamp.
- Wholesome Crossdresser: To get inside, Shaggy and Scooby drink a magic potion end up dressing like Daphne and Velma, respectively. This actually isn't the first film where they do it, as they also tried disguising themselves as Daphne and Velma in Scooby Doo! Pirates Ahoy!.
