When the Scooby-Doo gang takes a vacation to Atlantic City, they come across a sign for the circus, so Fred insists they visit that night. As it turns out, the circus doesn’t open till the next day, but Fred insists they look around. Eventually, they encounter Marius, the owner of the circus, and a werewolf. Velma eventually scares off the werewolf, and Marius tells the gang that the werewolves have been around everywhere stealing jewelry. The gang agrees to take part in the circus acts while the other members of the circus have been frightened away.
The film provides examples of these tropes:
- 2D Visuals, 3D Effects: The film blends traditional 2d animation with CGI, one notable example are the balls that Shaggy juggles around.
- Acquired Situational Narcissism: After their act in the circus proves to be a hit, Shaggy gets a swelled head and starts taking all the credit even though Scooby's the one doing all the work.
- Badass Biker: Daphne works as a motorcycle stunt artist as her cover.
- Black Comedy: Fred explains that when he was practicing on the trapeze before, he didn’t catch the person he was supposed to who fell and hit more people who hit the popcorn machine that fell over and caught the bleachers on fire and burned down the whole circus. He broke a lot of bones, none of them his.
- Bound and Gagged: Marius gets tied up and gagged twice.
- Cassandra Truth: Wulfric doesn't believe it when Phil tells him Scooby is a real dog instead of a man in a costume.
- Casting Gag: This is not the first time Maurice LaMarche voices someone involved with the circus.
- Circus Episode: This time the gang go undercover at the Brancusi travelling circus.
- Circus of Fear: The circus grounds are empty when the gang arrive, and Shaggy rates the place's creep factor as outranking an old cemetery on fire. It's better when the performers are there... unless the werewolves are too.
- Continuity Nod: From Phantosaur, Daphne’s biker skills make a return, and her lessons to Shaggy seem to have stuck (but he still hasn't learned how to brake).
- Crazy Jealous Guy: Oliverio, Lena's husband. He is extremely jealous whenever his wife flirts with anyone (which she does a lot). He seems to have a violent temper. However, he restrains himself to threats.
- Creepy Circus Music: The opening to the film, "The Circus Comes to Town" has a creepy circus vibe.
- Crouching Moron, Hidden Badass: In a chase scene atop a train, Shaggy brings down Archambault with tranquilizer darts.
- Died in Your Arms Tonight: In Shaggy's nightmare, Scooby gets bitten by a werewolf and collapses into his arms. However, he ultimately doesn't die; instead, the werewolf transformation works in reverse and turns him human.
- Dude, Where's My Respect?: Scooby really didn't like how critics praised Shaggy (and not him) on their performance together when he did all the work. He especially hates it when Shaggy takes all the credit.
- Easily Forgiven: Velma, Fred, and Daphne openly accuse Marius of being the werewolf, and he gets upset about it for about ten minutes. Neither party brings it up again. It's probably alleviated by the fact that the gang saves Marius' life when Archambault attacked him.
- Eating Pet Food: Animal trainer Doubleday absent-mindedly shoves a dog biscuit into Shaggy's mouth. Shaggy doesn't mind and eats it anyway.
- Eskimos Aren't Real:
- Shaggy doesn't believe in Sweden, thinking it's a made-up place like Fairyland or Australia. He also laughs at the notion that 5 o'clock in the morning is an actual time.
- Wulfric thinks Scooby is a guy wearing a dog costume and those who do believe Scooby is a real dog must be naive enough to think kangaroos are real.
- Fanservice:
- Daphne, especially in her dress and circus outfit. The clown outfit also qualifies.
- Lena, the female trapeze artist, wears form-fitting tights.
- Velma's costume comes with a skirt that doesn't show off her legs like the other girls, but her practice round as "the Human Comet" turns into a Naked People Are Funny gag when the cannon somehow blasts her outfit clean off. Velma emerges from the cannon, revealing her Shoulders-Up Nudity, and bashfully apologizes with, "Sorry. I think I tensed up."
- The 5 swimsuit-clad girls crowding around Shaggy at the beach (4 of them in bikinis).
- Go Through Me: In Shaggy's nightmare, he's having Scooby do tricks and soaking up the audience's approval when werewolves arrive. Scooby jumps between one and Shaggy and gets bitten.
- Groupie Brigade: Shaggy acquires a bunch of fangirls infatuated with him after being hailed as a circus superstar.
- The Guards Must Be Crazy: When the first werewolf is robbing the jewelry store, the security guard just runs into a pole and knocks himself out. Luckily, it's not a real werewolf.
- He Knows Too Much: When Doubleday says "You'll never take us that easy" while cornered by Mystery Inc., Archambault appears and tranquilizes Doubleday. It's soon revealed Archambault was Doubleday's appomplice and tranquilized Doubleday so he could have the black diamond and keep Doubleday from revealing his involvement to pull the pin. But unfortunately for him, Velma figures it all out just when it looks like Archambault gets away on the train.
- Heroic BSoD: Shaggy slumps into a depression when he realizes he’ll be performing in front of his favorite band.
- Human Cannonball: Velma's role in the circus for the film.
- Hyperventilation Bag: When Shaggy realizes that Wolfsmoon is going to be the audience for the upcoming performance, he begins hyperventilating. One of the others hands him a bag. He ultimately has to get another after breaking the first. Then Velma realizes she'll have to do the human cannonball act and steals the bag.
- I Never Said It Was Poison: One of the villains, Archambault, gives himself away by referring to the carbonado as the black diamond, despite supposedly having been kidnapped when the gang learned that carbonado referred to a black diamond.
- It Works Better with Bullets: One of the villains attempts to shoot Scooby with a tranquilizer gun, only to discover that Shaggy has taken the darts out of the gun.
- Kavorka Man: Shaggy scores some female fans after he gets credit for Scooby’s act. Even a few at the beach in their swimsuits.
- Leg Focus: Daphne has her long shapely legs highlighted through the tights of her purple mini dress and circus costume.
- Let's Split Up, Gang!: While they’re looking around the empty circus, Scooby and Shaggy run astray from the rest of the group twice, the second time with Velma.
- Eventually they do it again after being attacked in the city, but they end up with Fred.
- Mythology Gag: Not direct, but a group of people turning into werewolves, fear a gang member would turn too, a Scooby Doo hoax, and a real criminal chase in one time frame... are we referencing this movie or the 80s Scooby Doo series?
- Nice Job Breaking It, Hero: When Fred tries burying the werewolves in garbage, they avoid the attack, and end up covering the manhole into which Daphne and Velma just jumped.
- Non-Ironic Clown: Well there’s one, but the main clown is actually an actor who has unwillingly taken a job as a clown. His partner is the real clown.
- Only One Finds It Fun: While the gang are discussing what to do in Atlantic City, Fred sees a poster for the circus. The others aren't enthused, but he ultimately badgers them into it.
- Pink Means Feminine: Lena wear a pink leotard.
- Plot-Mandated Friendship Failure: Scooby gets angry at Shaggy for taking all the credit for their act, in which Scooby is the talented one.
- The Resenter: Whitney and Archambault resent their previous boss' nephew for taking over the circus instead of them.
- Right Behind Me: Shaggy is talking to the others about the werewolf when he notices them staring silently at him. He asks "You'd tell me if the werewolf was right behind me, wouldn't you?". Naturally, it is.
- "Scooby-Doo" Hoax: All staged by Doubleday and his trained baboons so that they could steal jewelry. Well, that’s what you might think if Velma didn’t figure out that Archambault was in on it and cut Doubleday off before he could say so. Apparently, both of them were mad that Marius’ uncle gave the circus to him instead of one of them, who had been working for him much longer.
- Series Continuity Error: Shaggy claims Australia is a made-up place, despite their visit in Scooby-Doo! and the Legend of the Vampire. Which might constitute a Negative Continuity. Or the films aren't released in order and they haven't been yet...
- Sexy Jester: Daphne's clown outfit is very sensual.
- Silent Snarker: When Shaggy suggests that the werewolf is female, Scooby gives him a stupid look.
- Statuesque Stunner: Lena. She is a tall woman with blonde hair and an athletic build.
- Strange Minds Think Alike: Both Shaggy and Wolfric don't believe in kangaroos.
- Suddenly Speaking: Sisko at first only appears to communicate by honking his horn, but turns out to be able to talk after his partner Schmatko leaves.Sisko: I thought he'd never leave.
- Surprisingly Realistic Outcome: Fred is impressed when Oliviero actually prevents him from falling and getting hurt during the high wire act in spite of implying that he'll let him fall as payback for Lena being attracted to him. Oliviero simply points out to Fred that following through on his threat would've caused him to get fired and blacklisted.
- Sympathy for the Devil: After Doubleday and Archambault are arrested, it's revealed that their primary motive was the fact that they were both angry with how Marius's uncle, who they had worked with for many years, had left the circus to Marius instead of one of them, and how Marius was "modernizing" the circus by doing things such as phasing out the trained animal acts (which left Doubleday out of a job) and giving it more of "theatrical" feel. Marius actually admitted that he could understand why Doubleday and Archambault were angry.
- The Tease: Lena, the trapeze woman, flirted with Fred Jones after he deliberately avoided looking at her.
- Top-Heavy Guy: Archambault is a big strong guy with small legs.
- Traintop Battle: Scooby and Shaggy face Archambault atop a train near the end of the film.
- Understanding Boyfriend: When Werewolf Lena comes out with the others, Oliverio approaches her and says he doesn't care whether she's a werewolf now; he'll willingly become a werewolf if he can stay with her.
- Wham Line: Before he gets tranquilized by Archambault, Doubleday says "You won't take us that easy!"
- Wolf Man: The circus is attacked by werewolves who steal jewelry from the audience members and turn the performers into werewolves. The werewolves were the disguises of Whitney Doubleday and his trained baboons.
- Would You Do It For A Scooby Snack?: Actually, Scooby-Doo wouldn't until Shaggy offered him 342 pounds of them.
- You Meddling Kids: After Whitney Doubleday is unmasked and captured, Velma says the mystery isn't over and Daphne agrees because she feels like a mystery isn't over until the bad guy gives the "you meddling kids" rant. Archambault is eventually exposed as a co-conspirator and gives the rant, making Daphne feel better.
- Your Mom: In the beginning, a pair of cops encounter one of the werewolves and one of them asks the other if the werewolf is his mom. The other cop eventually admits that the werewolf does look a bit like his mother.
