History WesternAnimation / HappyHalloweenScoobyDoo

* PoliceAreUseless: The gang frequently encounter a Sheriff (the same one from ''Curse of the 13th Ghost'' and ''Return To Zombie Island'') who constantly tells Mystery Inc. to [[ObstructiveBureaucrat leave things to the professionals.]] [[spoiler:Somewhat subverted later since as it turns out, he's actually a disgraced CEO named Cutler Toe that the gang unmasked in the past and impersonated a sheriff to try to break down the gang's morale so he could mine for lithium without their interference...not that the SWAT Team guarding Crane are that much better.]]

** Cutler Toe was a crook exposed in a past case that Velma calls "The Mystery of the Trash Monster of Scranton".

* AnAesop: It's okay to be afraid, so long as you don't let it control you.
** GreenAesop: To a lesser extent, it's a plot point that the true mastermind was trying to illegally obtain lithium that would cause catastrophic environmental damage.

* PoliceAreUseless: The gang frequently encounter a Sheriff (the same one from ''Curse of the 13th Ghost'' and ''Return To Zombie Island'') who constantly tells Mystery Inc. to [[ObstructiveBureaucrat leave things to the professionals.]] [[spoiler:Somewhat subverted later since as it turns out, he's actually a disgraced CEO named Cutler Toe that impersonated a sheriff to try to break down the gang's morale...not that the SWAT Team guarding Crane are that much better.]]

* CorruptCorporateExecutive: [[spoiler:Cutler Toe is behind the Jackal Lanterns as part of a plan to steal the lithium under the town and get even with Mystery Incorporated for ruining a past scheme of his]].

* BigBad: The Mystery Gang are fighting off Jonathan Crane this time. Yes, ''that'' [[Franchise/{{Batman}} Jonathan Crane]]. However, [[spoiler:it turns out that Crane himself is being framed, and he was only there to watch the parade and Elvira. The ''real'' BigBad is [[EvilAllAlong the Sheriff]], who is really Cutler Toe, a disgraced CorruptCorporateExecutive the gang had exposed in the ([[NoodleIncident unseen]]) past and came to Crystal Cove impersonating a sheriff and unleashed the Jackal Lanterns in a plot for revenge]].

* EnemyMine: [[spoiler:Scarecrow might be an unapologetic villain, but he does form a brief alliance with our heroes to take on the Alpha Pumpkin, especially since he might have already suspected Cutler Toe as the real mastermind and already has a grudge with him.]]

** The finale of the CreativeClosingCredits has Fred yell, "She's alive! She's alive!!" like [[Film/{{Frankenstein}} Dr. Frankenstein]] shouting, "It's alive!"

%% * GettingCrapPastThe Radar: Due to overwhelming and persistent misuse, GCPTR is on-page examples only until 01 June 2021. If you are reading this in the future, please check the trope page to make sure your example fits the current definition.

* AnimationLeadTime: Production started in 2019 (and in fact was originally intended to be released that year), but by the time it was released it was during the UsefulNotes/COVID19Pandemic which made Halloween celebrations like parades not exactly likely in real life, especially when there's no masks or social distancing. Although you could reasonably WildMassGuess that it didn't occur in this universe especially if they have the super-science of the DC Comics here.

* TwoFaced: [[spoiler:Excluding a new Mystery Machine being built during the credits, the movie ends with a hairless Elvira stating that the morals of the story are that you can get through anything with your friends and there's nothing to fear but fear itself..."and also this", she adds while turning her head 180 degrees to reveal a three-eyed, jagged-mouth, functional second face on the back of her bald head.]]

* BigBad: The Mystery Gang are fighting off Jonathan Crane this time. Yes, ''that'' [[Franchise/{{Batman}} Jonathan Crane]].
** [[spoiler: It turns out that Crane himself is being framed, and he was only there to watch the parade and Elvira. The ''real'' BigBad is [[EvilAllAlong the Sheriff]], who is really Cutler Toe, a disgraced CorruptCorporateExecutive the gang had exposed in the ([[NoodleIncident unseen]]) past and came to Crystal Cove impersonating a sheriff and unleashed the Jackal Lanterns in a plot for revenge.]]

* EveryCarIsAPinto: Many vehicles explode in this movie when they crash or are hit by something, [[spoiler:even the Mystery Machine!]]
** PlayedForLaughs in a ''[[WesternAnimation/TheSimpsons Simpsons]]''-esque fashion when the clown-themed party supply truck that is under control by the Jackal Lanterns nearly crashes into a tree, but its big red clown nose gently presses against the tree, and then the truck blows up a second later.

* {{Foil}}: Bill Nye for Jonathan Crane. Both are scientists, and both talk about logic and reason. While Nye is helpful and supportive of Mystery Inc., Crane is antagonistic and villainous. [[spoiler:At least until he distracts the Alpha Pumpkin to [[EnemyMine defeat a common enemy]].]]

* LoonyFan: As it turns out [[spoiler:this was Jonathan Crane's only motivation for going to the Halloween parade. He's a big fan of Elvira, even sending her a fan letter before his strike.]]
** [[spoiler:Daphne's attempt to subsume Elvira's life probably puts her in this category, as well. The gang mention that she's done this before; they once solved two mysteries with Phyllis Diller before they realized she and Daphne had switched places]].

** Daphne's desire to trade places with celebrities led the gang to solve two mysteries with Phyllis Diller before they wised up.

** [[spoiler: It turns out that Crane himself is being framed, and he was only there to watch the parade and Elvira. The ''real'' BigBad is [[EvilAllAlong the Sherif]], who is really Cutler Toe, a disgraced CorruptCorporateExecutive the gang had exposed in the ([[NoodleIncident unseen]]) past and came to Crystal Cove impersonating a sheriff and unleashed the Jackal Lanterns in a plot for revenge.]]
* BigNo: Fred, when [[spoiler:the Mystery Machine blows up (of course).]]
* {{Bookends}}: [[spoiler:When Scarecrow is arrested at the opening of the movie, Mystery Incorporated say he won't be terrorizing traffic on Highway 13 any more. At the end, he attacks Cutler Toe and his "very fast sports car" on Highway 13]].

* MutagenicGoo: The apparent source of the mutant pumpkins is a leaking tanker of toxic waste mixing with a canister of fear gas, which turns it from [[SicklyGreenGlow glowing sickly green]] to an [[SupernaturalIsPurple eerie purple]].

* AdultFear: Mike, as the father of a young girl, is also genuinely terrified of the situation. He almost declined to help Shaggy and Scooby over the risk doing so presented to him and his daughter evacuating when a fissure was opening in town.

''Happy Halloween, Scooby-Doo!'' is a movie in the long-running ''Franchise/ScoobyDoo'' [[WesternAnimation/ScoobyDooDirectToVideoFilmSeries direct-to-DVD movie lineup]] written and directed by Maxwell Atoms (''WesternAnimation/TheGrimAdventuresOfBillyAndMandy''). In this one, Mystery Incorporated must fight off Jonathan Crane a.k.a ComicBook/TheScarecrow, who has mutated pumpkins into his own savage Jack-o'-lantern army. Helping the gang are Creator/BillNye the Science Guy and Creator/ElviraMistressOfTheDark. Together, they must save Crystal Cove before Scarecrow's army plunges it into a never-ending nightmare.

* {{Crossover}}: This is the first direct-to-video animated film in which the gang will face off against a ''Batman'' villain[[note]]by themselves, not with the Caped Crusader[[/note]], ComicBook/TheScarecrow.

** Daphne's desire to trade places with celebrities led the gang to solve three mysteries with Phyllis Diller before they wised up.

* SaveTheVillain: Velma insists on saving Dr. Crane, but she also reminds herself of the story of the Scorpion and the Frog before doing so.

* FlatWhat: [[spoiler:How Scarecrow proves that it's ''definitely'' not him in response to learning about the Jackal Lanterns.]]
* FreudianSlip / FullNameUltimatum: '''Daphne''': "Frederick Herman Jones! Don't you torchsplain to me when I am carrying a torch for you!"

* AdaptationalComicRelief: [[https://youtu.be/sdgFlocdgp4 Maxwell Atoms]] said how Daphne here is like how she was in ''WesternAnimation/BeCoolScoobyDoo'', and as such, is much more of a silly goofball here.

* {{Bookends}}: [[spoiler:When Scarecrow is arrested at the opening of the movie, Mystery Incorporated say he won't be terrorizing traffic on Highway 13 any more. At the end, he attacks Cutler Toe and his "very fast sports car" on Highway 13.]]

* BullyingADragon: [[spoiler:Using one of Gotham City's most dangerous villains, The Scarecrow, as a patsy]] is definitely never a smart idea. [[spoiler:Cutler Toe]] was just [[LaserGuidedKarma asking for it]] for daring to try.

*** Related to that, there's a scene of a man with red, curly hair fleeing a truck labled "Red Herring's Party Scares"

* RewatchBonus: [[spoiler:Scarecrow is arrested in front of a "Red Herring's Party Scares" truck, foreshadowing that he is a red herring of the real mystery.]]

* DarkIsNotEvil: Elvira, Mistress of Darkness, of course.

** [[spoiler:Daphne's attempt to subsume Elvira's life probably put her in this category, as well.]]

* CardCarryingVillain: In addition to embracing the fact that he's insane, Scarecrow has ''absolutely'' no qualms in saying that he's a supervillain. If anything, he's disappointed that he's only ranked 53rd worldwide.